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Full text of "Radio Age (Jan-Dec 1924)"

Book _til___ 



Scanned from the collections of 
The Library of Congress 



AUDIO-VISUAL CONSERVATION ^0tmm- K ' "." — ^''TWlll 



at The LIBRARY of CONGRESS 





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ftr? ** 



Packard Campus 

for Audio Visual Conservation 

www.loc.gov/avconservation 

Motion Picture and Television Reading Room 
www.loc.gov/rr/mopic 

Recorded Sound Reference Center 
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The Magazine of 

JANUARY 
1^24 



This 

Number 



Construction of wave trap 
to make receiver selec- 
tive. 

A Good Neutrodyne 
Receiver. 

How to make a Junior 
Heterodyne. 

Simple Experiments in 
radio control. .^< 

What the Broadcasters 
are doing. 

Complete corrected list of 
Broadcasting stations. 

More good circuits. 





Let OurJIookripf Beybur Guide 



<tf ; ,^ 



Your Radio Problems Solved 
for 30 Cents in Stamps 



IF YOU are constructing a receiving set, a battery charger, a loading coil, a con- 
denser, or a transformer and you need help in the way of clear diagrams and full 
detailed descriptions of that very thing you may have it by return mail. 

We have laid aside a limited number of back numbers of Radio Age for you. Be- 
low we are listing the hook-ups and circuit diagrams to be found in these magazines. 
Select the ones you want, enclose 30 cents in stamps for each one desired. 

We advise immediate attention to this as the stock of back numbers is diminish- 
ing rapidly. 



May, 1922 

— How to make a simple Crystal Set for $6. 

June, 1922 

—How to make a Receiving Transformer. 
— Aerials under ground and under water. 
— Electric light wires as auxiliary to radio. 



September, 1922 

— How to construct the Reinartz Receiver. 
— Federal Act regulating radio. 



October, 1922 

— How to make a Tube Unit for $23 to $37. 
— How to make an Audio Frequency Amplifying Trans- 
former. 



November, 1922 

— Photo-electric Detector Tubes. 

— Design of a portable short-wave radio wavemeter. 



December, 1922 

— Home-made battery charger for $3.00. 
— Principles of radio receiving equipment. 



January, 1923 

— How to make a sharp-tuning Crystal Detector. 
— Fixed condensers in home-made receiving sets. 
— Description of loading coil for simple sets. 

March, 1923 

— Layout and drilling for Reinartz Tunar, with am- 
plification. 
— How to make the Crystal Set do long distance work. 
— How to make an Audio Frequency amplifier. 
— Symbols used in radio diagrams. 



April, 1923 

— The Kopprasch circuit. 

— How to make a one-tube loop aerial set. 

— A two-circuit Crystal Set. 

May, 1923 

— How to make the Erla single-tube reflex receiver. 
— How to make a portable Reinartz set for summer use. 

June, 1923 

— How to build the new Kaufman receiver. 
— What about your antenna? 

July, 1923 

— The Grimes inverse duplex system. 
— How to read and follow symbols. 
— Proper antenna for tuning. 

August, 1923 

— Construction of the Cookaday four-circuit tuner. 
— An efficient two-stage amplifier. 
— A simple buzzer transmitting set. 

September, 1923 

— How to load your set to receive new wave lengths. 
— Simple Radio Frequency Receiver. 

October, 1923 

— Tht Four-Tube Neutrodyne. 
—Your First Tube Set. 

November, 1923 

— The Super-Heterodyne. 
— A Three-Cirouit Tuner. 
— How to Learn Code. 

December, 1923 

— Building the Haynes Receiver. 

— Combined Amplifier and Loud Speaker. 

. — A selective Crystal Receiver. 



RADIO AGE, Inc. 



500-510 North Dearborn Street, CHICAGO, ILL. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 






q/ 




ADVANCE OF THE GRAND ARMY 

NAPOLEON'S name fills more pages in the world's solemn history than that of any other mortal. 
The advance of his Grand Army into Russia is the turning point of his career and marks the beginning of his downfall. 
During the World War mighty armies marched over the battlefields where Napoleon fought over a century ago. All the 
causes of this mighty struggle may be learned from the pages of history. The one complete, accurate, authoritative and 
reliable history, depicting the rise and fall of every empire, kingdom, principality and power, is the world-famed publication, 

Ridpath's History t World 

Including a full authentic account of the World War 

Dr. John Clark Ridpath is universally recognized as America's greatest historian. 

Other men have written histories of one nation or period — Gibbon of Rome, Macaulay 
of England, Guizot of France; but it remained for Dr. Ridpath to write a history of the entire 
World from the earliest civilization down to the present day. 

A Very Low Price and Easy Terms 

We will name our special low price and easy terms of payment 
only in direct letters. A coupon for your convenience is printed on the 
lower corner of this advertisement. Tear off the coupon, write your name and 
address plainly and mail now before you forget it. We wiU mail you 46 free 
sample pages without any obligation on your part to buy. These will give 
you some idea of the splendid illustrations and the wonderfully beautiful 
style in which the work is written. We employ no agents, nor do we sell 
through bookstores, so there are no agents' commissions or book dealers' 
profits to pay. Our plan of sale enables us to ship direct from factory 
to customer and guarantee satisfaction. -n 

Six Thousand Years of History 

D IDPATH takes you back to the dawn of History, 

**■ long before the Pyramids of Egypt were built; down 
through the romantic troubled times of Chaldea's gran- 
deur and Assyria's magnificence; of Babylonia's wealth 
and luxury; of Greek and Roman splendor; of Moham- 
medan culture and refinement to the dawn of yesterday, 
including a full authentic account of the World 
War. He covers every race, every nation, every time, 
and holds you spellbound by his wonderful eloquence. 

Endorsed by Thousands 

D IDPATH is endorsed by Presidents of the 

* * United States, practically all university and college 
presidents, and by a quarter of a million Americans who 
own and love it. Don't you think it would be worth 
while to mail us the coupon and receive the 46 sample 
pages from the History? They are free. 

Ridpath's Graphic Style 

T3 IDPATH pictures the great historical events 
■*- as though they were happening before your eyes; he 

carries you with him to see the battles of old; to meet kings and queeni 
and warriors; to sit in the Roman Senate; to march against Sal ad in and 
his dark-skinned followers; to sail the southern seas with Drake; to 
circumnavigate the globe with Magellan. He combines absorbing 
interest with supreme reliability. 

THE RIDPATH HISTORICAL SOCIETY 

HH9HUH CINCINNATI, O. ■mmwn 







*y 



THE 

RIDPATH 

HISTORICAL 

SOCIETY 
Cincinnati, 0. 
Oy^ Please mail, without cost 
<^/ to nie, sample pages of 
' ^Jy^Rldpath's History of the 
1\jT World, containing photogravures 
of The Surrender at Sedan, Napoleon, 
and other great characters in history. 
A?^/' Also write me full particulars of your 
Oyr special offer to Radio Age readers. 



NAME 



ADDRESS 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



RADIO AGE 

The Magazine of the Hour 

(Established March, 1922) 



Volume 3 



JANUARY, 1924 



Number 1 



CONTENTS 

Page 

Tuning Out Interference 5 

By Felix Anderson. 

The Junior Superheterodyne 11 

By John B. Rathbun. 

The Push-Pull Amplifier 15 

By Frank D. Pearne. 

The Rosenbloom Circuit 17 

By Frank D. Pearne. 

Pickups and Hookups , _ 19 

Little Things That Help. 21 

Radio Control Experiments 24 

By Carl Mas son. 

Substituting Tube for Crystal. 25 

By J. A. Callanan. 

How Receiving Tuners Work 26 

With the. Manufacturers.... 33 

The How and Why of the Neutrodyne 34 

Questions and Answers ...35 

Corrected List of Calls 43 

With Wave Lengths. 



Radio Age is published monthly by 
RADIO AGE, Inc. 

Publication office, Mount Morris, 111. 

Editorial and Advertising Offices, Boyce Building, 

500 N. Dearborn St., Chicago 

Frederick Smith, Editor 
Frank D. Pearne, Technical Editor 
M. B. Smith, Business Manager 
Louis L. Levy, Circulation Director 

Western Advertising Representatives 

BRUNS & MACDONALD 

First National Bank Building, Chicago 

Eastern Representatives 

E. V. HEVEY & COMPANY 

17 West 42nd Street, New York City 

Telephone, Longacre 1698 

Advertising forms close on the 15th of~the~month 
preceding date of issue 

Issued monthly. Vol. 3, No. 1. Subscription price $2.50 a year. 

Entered as second-class matter September 15, 1922, at the post office at Mount 

Morris, Illinois, under the Act of March 3, 1879 



Copyright. 1924, by RADIO ACE, Inc. 



Our Unique 
Record 

WITH this issue our magazine 
enters its third calendar 
year. We established it 
in the early spring of 1922 with a 
firm belief in the steadfastness of 
public interest in radio and results 
have amply justified our faith. We 
have attained a substantial pros- 
perity and as you readers have been 
partners in our enterprise, we be- 
lieve it not out of place to tell you 
just how we accomplished it. 

In the first place we regarded the 
selling of advertising space as of 
secondary importance. The pri- 
mary object was to print a maga- 
zine that radio fans would actually 
need in their home experimentation 
and in the construction of receiving 
sets and accessories on their own 
work benches. Our growth from 
10,000 to present figures with sub- 
scriptions and sales increasing 
rapidly from month to month, 
proves that our idea — service to 
readers first — was a sound one. 
No inconsiderable financial bur- 
den is involved in the writing, 
editing, illustrating, printing and 
distribution of 50,000 forty-eight 
page magazines every thirty days. 
Outside of printing costs, white 
paper bills, administration expenses, 
engraving costs, express and post- 
age there are scores of incidental 
items to swell the monthly total. 
Yet, like the Miller of the Dee, we owe 
no man a penny and our bankers 
greet us with a daily smile. Fans 
throughout Canada and the United 
States have built up RADIO AGE 
and they are adding to the structure 
every day. It is a readers' book. 

It is inevitable, with such a 
showing for this publication, that 
advertisers will want increasing 
space in which to convey their mes- 
sage to our 100% circulation. That 
brings us up to the most important 
point we wanted to make. With 
new advertising, additional pages 
will be added to the magazine so 
that the present generous allotment 
of space for readers will increase 
rather than diminish. We never 
had an ambition to edit or publish 
a catalogue. 

Wishing you a happy and pros- 
perous New Year — 

—Editor, RADIO AGE 



THE AIR 



I S 



FULL OF THINGS YOU SHOULDN 



MISS 




Radio has moved from the laboratory and 
amateur's work'table out into the re6ned 
surroundings of the family living room. 
In keeping with this new companionship 
we offer this reliable, long-lived Eveready 
**B" Battery, in an attractive, new meta I 
case, worthy to stand beside the rich 
■)inets of fine radio sets. 

Eveready "B", 22 !4 volts, 

No. 766 with Six Fahnestock 

Spring Clip Connectors. 



When Radio called, Eveready was ready 



TWENTY-ONE years ago, when wireless 
telegraphy had its first birthday, National 
Carbon Company's dry cell batteries were 
nine years old. Even then its batteries were 
world famous as convenient, economical and 
efficient sources of electric energy. 

With the introduction of broadcasting, 
radio leaped into universal service. Radio 
engineers used Eveready Batteries as their 
standard in designing tubes and receiving 
sets. Eveready engineers, backed by the 
most complete research and testing labora- 
tones known to the industry, worked with 



them to discover how the known dry cell 
could be improved for radio work. 

The fruit of these efforts is the Eveready 
family of radio batteries, conspicuous for 
vitality and endurance — the right battery 
by test and proof for every radio use. 

To be certain of battery satisfaction, 
insist on Eveready Radio Batteries — they 
last longer. All reliable radiodealers sell them. 

Informative and money-saving booklets on 
Radio Batteries sent free on request. 

National Carbon Company, Inc., New York, N. Y. 




Headquarters for Radio Battery Information 

If -you have any battery problem, write to Radio Division, Nationai Carbon Company, Inc. 
202 Orton Street, Long Island City, N. Y. 



Eveready Radio 4, A" 
Dry Cell 

Specially manufactured 

for use with low 

amperage tubes 



764 
The Space 
Saver 

Vertical 
nVi-volt 
"B" Battery 



No. 767 

"B" Battery, 45 volts 

Variable taps 

Fahnestock Clips 



Eveready Three 

or "C" Battery 

Clarifies tone and 

incteases "B" 

Battery life 




EVEREADY 

Radio Batteries 

- they last longer 




At the top is Miss Rachel M. Thompson, of Boston. She is a graduate of a radio school and lectures to boys 
on radio subjects. (Keystone Foto). At the bottom is Miss Catherine Jay Moore, first American girl to pick up 
English broadcasting stations. (Kadel & Herbert Foto). At the right is another picture of Miss Moore. She is 
adjusting the aerial on the roof of her New York home. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



mimin urn mi i mi i ii' hii 1 1 M in i ii in i n i i i rnnii mi ii 1 1 1 i mini 1 11 1 in in 1 1 i iim in i ii 1 1 n i i 1 1 1 ii i < 1 1 ) n u | xrccm: 




RADIO AGE 



PUBLISHER^ 



Tfie Ma^a^ine of tfte Hour 

PUBLISHED -MONTHLY 




,, I I I ! N I I I I !! I I ! I I I I I I I I ! I I I I I I I I I I I I I I I > I I I I > I I I 1 ' > I I I > I I I I I I I I I I I I I I I 1 I I I I I I I I I I II I I I I I H I I I I I I I I 1 I I I I 1 I 1 ULI I I I I I I I I I I II 

Tuning Out Interference 



INTERFERENCE is the bugaboo of 
the radio pastime. Every time 
the average listener turns on the 
filaments of his radio set, he has to con- 
tend with this difficult element in the 
course of his enjoying the delightful 
programs and entertainment provided 
by the great institution of broadcasting, 
and not infrequently has he turned away 
from the receiving set with some savage 
invective concerning the inefficiency of 
his receiver or the inadequate system of 
wave allocations. 

The entire broadcasting system is 
based upon the assigning of waves as 
widely different as possible to stations 
in close proximity, in order to maintain 
a well balanced system of wavelengths to 
keep the disorder caused by the clashing 
of undesired frequencies down to a mini- 
mum. In large cities where more than 
one powerful station is operated, the 
popular method seems to be an agreement 
between the various broadcasters as to 
the division of the periods of the day 
when certain stations are permitted to 
broadcast. 

This system usually is efficient as far 
as local broadcast listening is concerned, 
but to some fans, the thing seems a poor 
arrangement, due to the fact that he 
has no chance to listen to programs from 
distant transmitting stations. Many 
cities provide a specified night for the 
reception of out-of-town stations. In 
Chicago, this "silent night" has proven a 
popular evening among owners of high- 
powered receivers who are assured of 
programs from many directions. 

But the average BCL is not satisfied 
with only one night a week to listen to 
out-of-town programs, and in spite of 
the powerful interference created by his 
local station, will endeavor to reach 
out-of-town stations almost any time 
he operates his set. 

If his set is one of close tuning prop- 
erties, the feat can easily be accomplished, 
but more often it happens to be one of 
the single circuit type, a type very popu- 
lar with the newly initiated due to its 
extreme simplicity of tuning, construc- 
tion and the exceptional volume it 
affords, and the result is a bad perspec- 
tive on the merits of radio listening. 
With a single circuit set operated in 
close proximity to a powerful broad- 
casting station, the business of tuning 
is likely to be a farce. The signal of the 



By FELIX ANDERSON 

Technical Assistant, Radio Age 



BlNOlHd 

Post 




SKETCH BY 

'ffax and£gson 



Figure 1. Isometric sketch of the Simple Series Eliminator. The condenser is a 23- 
plate, and the coil has 40 turns of No. 28 DCC wire wound on a three-inch cardboard tube 
A filter of this type is useful in assisting to tune out interference from nearby stations. 



local station can usually be heard over 
the entire tuning range of the set, and 
even if a distant station can be tuned in, 
it is usually so badly distorted and 
intermingled with noises and squawks 
from the local station that its entertaining 
value is lost. 

With the intention of alleviating the 
nuisance of interference to a minimum, 
the writer has compiled the following 
data to be applied to specified forms of 
interference, squawks, noises, howls, etc., 
and sincerely hopes that it may be the 
solution of the problem for many readers. 

Antennae 

Under first consideration comes our 
old friend, the antenna. For those who 
live at a reasonable distance from broad- 
casting stations and who are using tuners 
of either the single circuit or four circuit 
or any other type of set which tunes 



moderately closely, and who experience 
only little or occasional interference, it 
is recommended that they merely cut 
down on the length of their antennas. 

At a slight sacrifice in signal strength, 
the antenna may be reduced to eighty- 
five or ninety feet, including lead in, 
and the selectivity of the set increased 
materially. This applies to any type of 
receiver. With a two variometer vario- 
coupler (three circuit) receiver, the 
operator can then tune out any station 
at will, providing the interference is not 
on the same wave as the one to which 
he is tuning. Usually this slight change 
will solve the problem for the average 
BCL who fortunately has been accorded 
with a location where he may listen to 
programs from any such stations as he 
may care to tune. 

On the other hand, we have the fellow 
who lives about two blocks from a five- 



RADIO AGE — "THE MAGAZINE OF THE HOUR" 



OwpfMSSJ? 



&Af0/H6 J°asr 




Posr *2 






Figure 3. An isometric sketch of the wave trap, showing the method of connecting 
and arranging the apparatus. The wave trap is a useful instrument for tuning out many 
kinds of interference. 



may result in losses which may offset 
the merits of the filtering action. 
The Wave Trap 

The wave trap, sometimes called an 
"anti-resonant circuit," also is useful 
in tuning out undesirable signals of the 
broadcasting type. 

The apparata used in this unit are: 
one twenty-three plate venier condenser, 
one coil of 42 turns, wound on a three- 
inch untreated cardboard tube, a panel, 
cabinet and binding posts. 

The apparatus is arranged on the panel 
as shown in Figure 3, and should be 
connected to the set as shown in Figure 4. 
Binding Post 1 is connected directly to 
the antenna, while No. 2 is connected 
to the antenna post on the receiving set. 

This unit instead of being tuned to the 
frequency of the desired signal is tuned 
to the wave of the interfering signal. It 
will be noted that when the condenser 
of the trap is turned, the signal will 
diminish in strength until it disappears 
and then gradually increase again until 
it is restored to normal value. 

The trap should be adjusted to the 
point where no signal from the inter- 
fering station is heard. The receiver 
is then tuned to any other wave except 



hundred watt broadcasting station, with 
resultant harmonics from the guy-wires 
of the station, the transmitter itself, 
and from signals reradiated by his neigh- 
bors' receivers. His problem is "a horse 
of a different color," but can usually be 
taken care of by using what is known as a 

^TT AEZAL 

BWW6P0ST 1 




Figure 2. The electrical connections of 
the Simple Series Eliminator. 

Simple Series Eliminator 

The simple series eliminator, consisting 
of a filter or a series capacity-inductance 
circuit, connected across the antenna and 
ground posts of the receiving set, is of 
material assistance where a broadcasting 
or spark station is strong enough to 
render the tube inoperative. It is also 
useful in assisting to tune out spark 
stations on waves materially longer or 
shorter than the desired frequency. 

This simple unit is composed of a good 



twenty-three plate condenser, preferably 
with a vernier, and a one microhenry 
inductance coil. The coil may be home 
made by winding about forty turns of 
No. 28 DCC wire on a cardboard tube, 
three inches in diameter. 

The action of this type of filter is to 
provide a path whereby the interfering 
signals may be shunted off to the ground 
and not enter the receiving set. A filter 
of this type is not exceptionally close 
tuning, but will help matters along greatly 
as stated in the aforementioned cases. 

The connections of this type of filter 
are shown isometrically in Figure 1, and 
the electrical connections to the receiving 
set in Figure 2. The binding post shown 
numbered as Binding Post 1 should be 
connected to the antenna, and then to 
the antenna post of the receiver, while 
number two should be connected to the 
ground post of the receiver. 

Care should be taken in the construc- 
tion of this unit, as careless construction 



AE0AL 



BIND/I& f&T Z 




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ssr 



6ROUND POS7 
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OfXXJHP 



Figure 5. This shows another method 
of connecting the wave trap to the receiving 
set. 



T^ 4BRIAL 



AMENNfl POSr 



&ROOND POST 

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Figure 4. The wave\trap is connected in 
series with the aerial and set as shown 
herewith. The construction of this unit is 
described in detail in the accompanying 
article. 



the one to which the wave trap is ad 
justed. 

The action of a filter of this type ib 
that when it is tuned to resonance with 
the interfering signal, a local current 
flows around it, setting up a potential 
across its terminals almost strong enough 
to counteract the incoming wave from 
the interfering station. This action 
virtually obliterates any current of the 
interfering wave, and very little of it 
gets into the receiving set. If the station 
is exceptionally strong, one or more of 
this type of trap may be placed in the 
antenna lead, and tuned to the same 
wave or to separate waves which are 
causing interference. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



8/NOM Post 



&/W/A/6 />ar *J 



TWO iAVER COIL 




SWJTtH* 7APS 



SKETCH BY 
FEUX ANDERSOM. 



Figure 6. The isometric arrangement of the Eliminator. 



The extreme flexibility of this type of 
filter makes it a popular type of arrange- 
ment used to eliminate interference. 
When connected to the antenna in this 
manner, however, it is of little use in 
tuning out spark stations and to gain 
this additional advantage the filter must 
be connected into the circuit as shown 
in Figure 5. The Binding posts, num- 
bered 1 and 2, are connected to the 
antenna and ground posts of the receiver, 
respectively. The filter or trap then 
becomes an acceptor, and shunts the sig- 
nal, to which it is tuned, off to the ground, 
allowing the signal we want to pass on 
to the remainder of the set where it is 
amplified, rectified, distorted, etc. How- 
ever, the usefulness of the wave trap is 
limited to the eliminating interference 
of stations or signals which are separated 
by a rather wide band of waves, and 



cannot be used efficiently where only a 
few meters discrepancy exists between 
the interfering and the desired signal. 
This type of interference is a rather 
difficult problem, but can readily be 
handled by a filter of the coupled in- 
ductance type. 

The filter illustrated isometrically in 
Figure 6 is about the most efficient possi- 
ble arrangement available for tuning out 
interference from broadcasting stations 
or other stations using continuous wave 
transmitters. It really weeds out signals 
not wanted to a degree where tuning may 
be accomplished to within wavelengths 
differing by about one per cent of the 
desired signal, and therefore we will 
call it an "eliminator." 

The Eliminator 

The eliminator has many advantages 
over the other types of filters. Instead 



of placing the filter directly in the antenna 
circuit it is coupled to the aerial circuit 
on the same principle of the variocoupler. 
The aerial is inductively coupled to 
the filter with a small coil of wire wound 
directly outside of the filter coil. The 
inductive relation between the two coils 
and the capacity (condenser) are the 
components used to trap the interfering 
signal. 

The apparatus required in the course 
of construction of this type of filter are 
as follows: one twenty-three-plate vari- 
able condenser with vernier; one bakelite 
panel; two binding posts; one switch 
lever; three switch taps; two feet of 
rubber insulating tape; one cardboard 
tube about three inches diameter and 
three inches long; about seventy feet 
of No. 28 DCC wire; about eight feet 
of No. 24 or 26 DCC wire; empire cloth 



RADIO AGE — "THE MAGAZINE OF THE HOUR" 





A&/AL 






Figure 7. This shows the method of winding the inductances used in the Eliminator. 
Full details in accompanying article. 

or dry writing paper; busbar, solder and 
other accessories. 

Construction 

The construction of a filter of this 
type is a little more difficult than any 
of the ones described in the preceding 
paragraphs, but at best, the Eliminator 
is a simple piece of apparatus. 

The cardboard tube on which to wind 
the coils should be thoroughly dried and 
some moisture-proof compound should 
be applied. Soaking the tube in hot 
paraffine is good, as is shellac or collodion 
(airplane wing dope). 

Punch two holes about three-fourths 
of an inch from the side of the tube and 
wind about 40 turns of the No. 28 DCC 
wire running the finishing end through 
two more holes punched near the finish 
edge of the coil . Over this wrap three 
or four turns of the empire cloth or writ- 
ing paper and then start winding the 
primary (antenna) coil. 

The antenna coil consists of eight 
turns of the No. 24 or 26 DCC wire. 
Wind three full turns, and then bring 
out a small loop for a tap, wind two more 
and twist another tap, and then finish 
the coil by winding the remaining three 
turns, leaving ends at both the start 
and finish of the coil for connecting 
purposes. The taps three and five and 
the finish end of the coil are connected 
to the three switchtaps on the panel. 
Figure 7 shows the winding of the coil 
in cross section, with the following legend 



applying to the letters. A is the card- 
board tuning, B the 40 turns of No. 
28 DCC, C is the layer of writing paper 
or other insulation, D is the antenna 
coil, E the first and eighth turns on the 
antenna coil, and G is a strip of insulat- 
ing rubber tape used to bind the coil 
together. Three and five are the taps 
brought out to the switchtaps. 

Connect the forty turn coil ends to the 
condenser terminals as shown in Figure 
6. After making sure that the coil9 
are wound in the same direction, con- 
nect the first turn to Binding post 1 
and the third, fifth and eighth turns to 
the switch taps in order. The switch 
lever is then soldered to Binding post 2. 
This completes the wiring of the Elimina- 
tor. Simple, isn't it? 

How to Use the Eliminator 

If you are having trouble with broad- 
cast interference, fasten Binding post 
No. 1 to the antenna, and Binding post 
No. 2 to the set, and tune the filter to 
the interfering wave, in the same manner 
as described for the wave trap. Then 
let it alone and forget it for the rest of 
the evening. Connections illustrated in 
Figure 8. 

If you experience trouble with spark, 
AC hum, or arc light interference, con- 
nect the Eliminator as shown in Figure 

9, and notice how much better the set 
tunes. When using the Eliminator 
in this way, it will usually entirely 
squelch the interference caused by a 
broad spark set. 

A combination of the two arrange- 
ments may be used as shown in Figure 

10, and if it still leaks through, there is 
something radically wrong with the 
adjustment of the transmitting stations 
wave. 

General Suggestions 
The secret of these filters lies in con- 
structing them carefully, with low loss 
apparatus. In choosing a condenser, 
it would be wise to acquire one that has 
the rotary plates connected to the end 
mounting, and having but little insulat- 




Arfl&(HA post 



SBT 



o 




6f?D(jML> 



Figure 9. This shows the Eliminator 
used as a by-pass for interfering frequen- 
cies. The filter is connected directly across 
the antenna and ground posts of the receiv- 
ing set. 

ing dielectric which is so placed to assure 
but little leakage. Verniers of the 
friction type or gear type are to be 
desired over those having separate ver- 
nier plates. 

Above all, do not dope the wire of the 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



AERIAL 




GMML 



coils, and make all connections solid 
with solder and flux, cleaning the con- 
tact points well to cut down the high 
frequency resistance of the entire unit. 

These little details may not be notice- 
able if you make them one at a time, but 
counting them together, probably will 
make a great difference in the tuning 
qualities of the filter as a whole. 

Remember that no man can tune out 
a station if it happens to be plop on the 
wave you are listening on. If station 
ABC is transmitting on the same wave 
as XYZ at the same time, there is no 
receiver that will efficiently tune either 
of them out. 

Intelligent operation of these units 
and familiarization with their various 
traits is necessary just as much as 
patience is necessary in the process of 
learning to tune a new receiving set. 

The writer would be pleased to hear 
from readers who construct any of these 
types of interference preventers. 



Radio Widowers 

WEAF has received a number of letters 
of complaint from anxious husbands 
who find that their wives are neglecting 
their household duties because of the 
radio. One radio listener wrote request- 
ing WEAF's schedule to be changed so 
that broadcasting only take place on 
alternate evenings in order that she 
have ample opportunity to catch up 
with her regular duties. It is under- 
stood that no one is compelled to listen 
to WEAF but those who do so may 
gain sufficient profit from the Thursday 
morning programs especially arranged 
for women to make up for the time lost 
on other hours of the schedule. 

"An old farmer inherited some money." 
wrote one of WEAF'S listeners, "and 
went to the Waldorf to spend some of it." 



Figure 10. This shows the two filters of the Eliminator type used on a set. With the 
arrangement shown, interference can almost be considered negligible, provided the filters 
are well constructed. 



Said he to the clerk, "What time do you 
have meals?" "Breakfast from 6 until 
11, luncheon from 11 until 8 and dinner 
from 8 to 11," answered the clerk. "My 
goodness," exclaimed the farmer, "when 
do you expect me to see the city?" 

And then the writer went on to say: 
"The point is, if WEAF gives such 
wonderful programs all day and half 
the night, when am I going to do my 
housework and shopping? It is all 
too good to miss!" 



Radio Saves Reporter 

A somewhat tardy reporter, although 
it must be admitted, one with initiative, 
saved himself from being scooped on a 
local Capital story, through using his 
head and radio. He may have saved his 
head also. 

It was Sunday. He had tickets to an 
entertaining matinee. He went intending 



S/ND/N6 Post ± 

s*£/M'-Al6 POST 2 



■— O- 



tz 



framnmn 



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GROUND 



Figure 8. This shows the method of 
connecting the Eliminator to the receiving 
set. The Eliminator is the best all-around 
unit known as yet to tune out interference 
from any source. 



to leave in time to make the trip to a big 
cathedral on the outskirts of Washing- 
ton, get the speech of a celebrated divine, 
and return to the office to write his story 
for the morning. But he stayed so long 
at the theatre, he could not get to the 
cathedral in time, even with a taxi or an 
airplane. 

Suddenly he recalled that WCAP was 
broadcasting the ceremonies and that 
there was a receiving set at the Press 
Club. He was saved. Rushing to the 
club, he tuned in, and leisurely made 
notes during the discourse of the speaker. 
Later at the office he pounded out a neat 
half column and went home; saved by 
the radio — if the city editor doesn't find 
it out. 



Panel Treatment 

For the old panel that you have grown 
tired of looking at — for the new panel 
that you know will soon become thumb- 
printed and for the rest of them, try this 
stunt to treat the surface and get in re- 
turn, that dull finish and one that is 
easier kept neat and clean and something 
out of the ordinary. 

For the first treating, secure very fine 
sandpaper or emery cloth and rub down 
until the entire finish is removed. Care- 
fully brush all the dust off after this and 
with a soft cloth, apply thin oil and rub 
until it has disappeared. 

After this comes the finishing coat 
which must be applied in only one direc- 
tion and that, the lengthwise of the 
panel. Fine steel wool rubbed the long 
ways of the panel gives or rather leaves 
the grained finish yet a dull lustre ap- 
pears. One's own judgment must be 
used when the panel has been sufficiently 
polished in this manner. 

This application is especially recom- 
mended for the amateur who scratches 
up the panel in boring out the holes for 
the radio parts. This will cover up a 
multitude of sins in that direction and 
must always be done when the panel is 
unmounted. 



10 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 




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92 




RADIO AGE— "THE MAGAZINE OF THE HOUR" 



11 



A Junior Super-Heterodyne 

By JOHN B. RATHBUN 



DURING the past twelve months 
we have witnessed a number of 
rapid and radical changes in 
radio fashions, particularly in the design 
of high power multi-tube sets, and from 
all present indications we are getting 
all set for still another radical departure 
— the super-heterodyne circuit. During 
last December (1922), the majority of 
the radio experimentalists were busily 
employed in tinkering with straight 
radio frequency or with the Armstrong 
super-regenerative circuits. The "super" 
circuits in most cases did not live up to 
expectations and by the first of the year 
all interest in this receiver had prac- 
tically died out. The straight radio 
frequency circuits of that period were 
far from satisfactory. Hence, when the 
reflex circuit was announced, the tinker- 
smiths went at the new problem with 
great enthusiasm. 

After "reflexing" all spring and part 
of the early summer, and after we were 
getting up to the point where we could 
show some real results with the reflex 
receiver, up popped Hazeltine's neutro- 
dyne. At last we had found a solution 
for our former difficulties with the 
straight radio frequency hook-ups and 
the neutrodyne went merrily on, and 
in fact is with us today as one of the 
most prominent of hook-ups. While 
the neutrodyne proved a far more satis- 
factory circuit for the beginner than the 
R. F., or reflex type, yet there was some- 
thing lacking that discounted it in the 
eyes of the more advanced students of 
radio. We soon found that the neutro- 
dyne had very certain limitations and 
therefore determined to go farther afield 
to find the ideal in the super-heterodyne. 
Whether the latter will prove as prac- 
ticable and popular as the neutrodyne 
is still a question, but there is one thing 
certain, and that is, no other existing 
circuit can hope to equal it in efficiency 
and performance. 

Strictly speaking, the super-hetero- 
dyne is far from being a new circuit, 
but owing to the complication and 
expense of building it in its original 
form, it was so seldom spoken of that 
it is a decided novelty to the radio novice. 
The very mention of it was sufficient to 
send goose pimples down the spine of 
the unitiated until about a month ago 
when the first real attempts were made 
at the simplification of the circuit. 
Very possibly it will be as familiar to 
the novice within the next month or so 
as the straight regenerative or reflex 
circuits — there is no real reason why 
this should not be the case. At any rate, 
the super-heterodyne is the new star 
on the radio horizon and it will therefore 
be well for us to become acquainted with 
the general principles of the receiver and 
its simpler practical forms. 

Formerly, when one spoke of the 
"Rolls-Royce of radio" it brought visions 
of long vistas of tubes and control'knobs — 



//VF'UT 
■S/DE 





ouTFirr 



^■/L XVrtf/V 7" A7ETU/PA/ L/A/E 



-HtMI'I'I'liK 

Bl 



Fig. 1. 



a veritable tube exhibit of the first 
degree. Actually, however, this need 
not be the case, for the elementary 
circuit can be made nearly as simple 
in construction and as easy to control 
as the more common straight regenera- 
tive and at the same time, retain a con- 
siderable proportion of its inherent high 
power of amplification and range. Tube 
for tube, it will be found far superior 
to any of the popular high power cir- 
cuits yet devised, both in regard to signal 
strength and range. Further, it is not 
particularly critical or hard to tune, and 
its great selectivity alone should put it 
in popular favor even though its other 
virtues were of the ordinary order. 

General Principles 

It has long been known that far greater 
amplification is possible with long wave 
lengths bordering on 5,000 meters than 
with the ordinary short broadcasting 
waves lengths reaching a maximum 
at about 600 meters. In other words, 
far greater amplification is attained with 
a radio frequency receiver on long wave 
lengths than with short wavelengths. 
Further, there is one definite wave 
length on which amplification 'reaches 




a maximum in a given circuit, and if the 
wavelength is above or below this 
critical value, the amplification will 
suffer accordingly. This means that the 
ideal receiver would be confined to one 
definite wavelength and that a . long 
one when compared with that of the 
ordinary broadcasting station. 

With these facts in mind it is at once 
evident that we must provide some 
means for converting the various short 
broadcasting waves into a long wave 
of constant length before the radio energy 
enters the amplifying circuit if we are 
to attain the greatest benefit from our 
apparatus. In other words we must 
provide a "frequency changer" for con- 
verting the 300 meters of Station X, 
and the 550 meters of Station Y, into 
one constant wavelength in the order 
of 5,000 meters. When this conver- 
sion has been performed, the converted 
radio waves pass to the radio frequency 
amplifying stages for intensification, 
thence through the usual detector tube 
and then through the audio amplifica- 
tion stages, should audio amplification 
be considered necessary. Back of the 
frequency changer, we have a circuit 
which is identical with that of the 
ordinary radio amplification set. We 
may have as many radio or audio stages 
as we desire, or rather as many as we 
can afford. Even one radio stage, 
detector and one audio stage are possible. 

Before going further with a descrip- 
tion of the circuit, we wish to call the 
readers' attention to the relation between 
"wavelength" and "frequency." The 
wavelength of a radio wave is the dis- 
tance between the peaks of the radio 
wave measured in meters. The frequency 
of the wave is the number of complete re- 
versals taking place in the wave per sec- 
ond; that is, the number of times that 
the wave surges back and forth (two 
trips) per second. Since the radio wave 



12 



RADIO AGE — "THE MAGAZINE OF THE HOUR" 



progresses at a constant speed forward, 
approximately 186,000 miles or 300,000,- 
000 meters per second, it will be seen 
that the wavelength must bear a definite 
relation to the frequency. In short, 
the velocity of the wave in meters per 
second, divided by the wavelength in 
meters, gives the frequency in "cycles 
per second" or the number of complete 
reversals per second. In the descrip- 
tion that follows, it is much simpler to 
speak in terms of the frequency than in 
terms of the more commonly used "wave- 
length," but in any event the total result 
will be the same. 

For example, a wavelength of 360 
meters corresponds exactly with a fre- 
quency of 833,333 cycles per second, 
429 meters wavelength corresponds to 
700,000 cycles per second, and so on. 
The longer the wavelength the less will 
be the frequency in cycles per second, 
the shorter the wavelength the greater 
will be the cycles per second. One 
increases as the other decreases, in direct 
proportion. 

Heterodyning 

As before explained, we must first 
reduce the frequency of the rapid broad- 
casting wave to a frequency of approxi- 
mately 60,000 cycles per second (5,000 
meters wavelength), before passing the 
energy to the radio amplifying tubes of 
the super-heterodyne circuit. Thus, 
if the station is broadcasting on 429 
meters wavelength, we must reduce the 
station frequency of 700,000 cycles per 
second to a frequency of 60,000 cycles 
in the amplifier circuit. This is performed 
by what is known as the "heterodyne 
method" in which an interference is 
produced between the incoming radio 
waves and the waves or oscillations set 
up by the "oscillating tube" in the receiv- 
ing circuit. 

By allowing the tube to oscillate at a 
certain frequency, and combining these 
oscillations with those of the incoming 
radio waves (at another frequency) 
we can obtain a resultant frequency 
equal to that required in the amplifier 
circuit. For example, let us say that the 
incoming waves from the station have a 
frequency of 600,000 cycles per second, 
and that the oscillations set up in the 
circuit by the oscillator tube is equal to 
500,000 cycles per second. The resulting 
oscillations of the combined waves will 
be equal to the difference of the two 
frequencies or: 600,000-500,000 = 100,- 
000 cycles per second. This means that 
the oscillations have been reduced from 
600,000 to 100,000 cycles per second in 
the amplifier circuit. By adjusting the 
oscillator tube by means of a variable 



INPUT 




condenser any desired resultant 
quency can be obtained in the same way. 
The oscillator circuit is the distinguish- 
ing feature of the super-heterodyne and 
is an essential part of the system. Elec- 
trically, the oscillator is quite simple 
as it consists of an inductance coil, an 
ordinary amplifier tube and a variable 
condenser, all of which are inductively 
connected to the usual tuning circuit 
through a few turns of wire somewhat 
like a fixed condenser. Varying the 
capacity of the circuit by means of the 
variable condenser varies the oscillation 
frequency of the tube. We now have two 
principal controls, (1) The tuning devices 
of the usual type, and (2) The control 
of the oscillator circuit or of the amplifier 
frequency. 

Simple Oscillator-Tuner Circuit 
An ordinary simple tube receiving 
circuit is shown by Figure 1 where (L) 
is a simple slide tuning inductance, 
(Cl) is the primary tuning condenser 
and (VI) is the detector tube. You 
have seen this typical circuit hundreds 




s?vo/o 



OSC/LL^TO/? 
C/ffCU/T 



-Ml 

Fig. 3. 

fre- of times if you have read RADIO AGE 
regularly. It is just an old-fashioned 
nonregenerative circuit first shown alone 
so that further developments can be 
more easily followed. This is the "tuning 
circuit," which of course can be modified 
by the substitution of a variocoupler 
for the inductance (L). 

In Figure 2 we have the "oscillator 
circuit" drawn out alone where (I) 
is the inductance coil, with a connection 
(a) to the mid-point of the winding. 
The oscillator tube is (V2), and the 
variable condenser used for controlling 
the frequency of the oscillations is at 
(C2). So far — so simple. The oscillator 
tube is supplied with the "B" battery 
(B2) which is entirely independent of the 
battery (Bl) in Figure 1. 

Since the oscillations of the tube 
(V2) must be impressed on the tuning 
circuit, we show the combined tuning 
and oscillator circuit in simple form by 
Figure 3. Here the old tuning circuit 
of Figure 1 and the oscillator of Figure 
2 are coupled together inductively by the 
coils (P) and (R). This is the funda- 
mental circuit of the super-heterodyne 
shown in its simplest form. The output 
(y-y) leads directly to the transformers 
and tubes of the radio frequency amplifier 
division, and from this point on the rest 
of the circuit is almost identical with 
an ordinary radio frequency receiver. 
We can have any reasonable number of 
radio frequency stages from this point 
on, ranging from one stage to five. A 
second detector tube follows the radio 
stages, and then comes the audio ampli- 
fication stages. It should be noted that 



RADIO AGE— "THE MAGAZINE OP THE HOUR" 



IS 



the super-heterodyne uses two detector 
tubes, one in the tuning circuit and one 
placed after the R. F. stages. 

A schematic view of the complete 
super-heterodyne assembly is given by 
Figure 4, it being assumed that each of 
the three principal divisions is contained 
in a separate cabinet for convenience. 
In the first cabinet (1) are the oscillator 
and first detector tubes which give this 
division the name of the "Tuner-Oscil- 
lator Unit." The output of (1) is con- 
nected to the input of the "Radio-Fre- 
quency Unit" marked (2). Here the 
radio waves are amplified on the long 
wave length produced by the first unit, 
and are then rectified by the second 
detector tube which is ordinarily placed 
in (2). The output of (2) is then con- 
nected to the input of the "Audio Ampli- 
fying Unit" marked (3) where the volume 
of the sound is augmented by familiar 
means. The output of (3) then goes to 
the loud speaker. 

It should be particularly noted that 
almost any type of tuner circuit can be 
used, either with an outdoor aerial, indoor 
aerial or loop aerial. Owing to the great 
powers of amplification possessed by this 
circuit, the loud speaker can be operated 
with good volume on stations several 
thousand miles distance, the exact 
volume of course depending upon the 
number of amplifying stages used. For 
convenience we have shown the ordinary 
flat-top outdoor aerial in the illustrations. 

Radio Frequency Unit 

Almost any type of radio frequency 
hook-up can be worked at (2), resistance 
coupling, transformer coupling or by 
tuned impedances. Probably, the trans- 
former connected type with special 
long wave length transformers is the 
most common type, but not necessarily 
the most effective. However, no matter 
what class of stage coupling is used, there 
is one thing that we must keep in mind 
from first to last, and that is, that we 
are dealing with wavelengths in the 
nature of 5,000 meters in this circuit 
and that the ordinary short wavelength 
transformers and impedances are there- 
fore absolutely useless with the super- 
heterodyne. The R. F. transformers 
used in reflex circuits and designed for 
wavelengths ranging from 200 to 600 
meters are a hindrance rather than a 
help. 

Outline of the "Junior" 

In presenting the "Junior" super- 
heterodyne circuit the principal objective 
is simplicity and economy, with flexi- 
bility in regard to future expansion a 
close second. Starting with five or six 
tubes as a basis of operations, this being 
the smallest number of tubes which will 
insure the performance characteristic of 
the super-heterodyne, we can afterwards 
add more radio or audio stages as we 
may desire without tearing up the tuner- 
oscillator unit. As with any other 
circuit, the greater the number of ampli- 
fying stages, the greater will be the range 
and volume, and we can carry this up 
to ten or twelve tubes if our pockets will 
bear the traffic. 

However, we have assumed that there 
are but few millionaires among our 



#. 




SAFETY FIRST 
Many an amateur radiophan has learned to his dismay that 90 volts "B" 
battery accidently connected across the filament of the tubes is an expensive 
mistake. An excellent method for testing, etc. is to hook a 110 volt, regular 
house lighting bulb in series with the minus lead of the B battery. The 
bulb acts as a safety valve, allowing the current to pass freely to the tubes on 
the plate, but should the connection be wrong, only six volts will fill the tube, 
the excess current being absorbed by the bulb, — result $5 to $40 saved for 
Mr. Experimenter (Foto Topics). 



readers and therefore have confined 
ourselves to a five tube set, oscillator 
tube, frequency changer tube, two stages 
of radio amplification, and detector. 
If more volume is required, then two 
stages of audio can be added to the out- 
put in the usual manner. As the audio 
stages are ordinarily installed in a sepa- 
rate cabinet, the addition of these stages 
will in no way affect the Tuner-oscil- 
lator or the radio stages. Regeneration 
in the tuner circuit undoubtedly increases 
the effectiveness of the set, but in return 
makes it very difficult to tune. Every 
time that the tickler coil is moved, it 
upsets the rest of the circuit and we must 
then make a second or third trip over 
the dials to bring the circuit back into 
resonance. This feature can be added 
later if desired, after the builder becomes 
more familiar with the action of the 
circuit. 

A unit construction has been adopted 
which makes the set simple to build and 
makes it much more compact than with 
the ordinary type of construction. In- 
sofar as possible, the inductances have 
been mounted directly upon the variable 
condensers a la neutrodyne. In the 
near future it is likely that such units 
can be purchased ready built upon the 
open market, thus adding to the ease 
and certainty of construction. 

Tuning Circuit 

Figure 5 gives the complete circuit 
diagram of the "Junior" super-hetero- 
dyne, and it will be noted that the tuner 
oscillator unit and radio frequency unit 
are boxed off in dot and dash lines] to 



indicate the separate cabinets in which 
the apparatus is installed. 

The first circuit to demand our atten- 
tion is the tuning circuit, and this will 
be seen to consist of a fixed coupler (Ll- 
L2) of the neutrodyne type which is 
tuned in the secondary circuit by the 
variable condenser (CI). The neutro- 
dyne fixed coupler has often been de- 
scribed, but we may say that the pri- 
mary coil (LI) consists of 15 turns of 
No. 20 D. C. C. wire wound on one end 
of a three-inch tube, while the secondary 
coil (L2) is wound on a 3 1-2 inch tube 
and consists of 66 turns of the same size 
wire. The primary winding is now placed 
inside the tube containing the secondary, 
and the relation between the coils is 
fixed by securely fastening the two 
tubes together at their ends. The 
tuning condenser is a variable vernier 
type with a capacity of 0.0005 m. f., 
and is the only tuning element used. 

A UV-201A or a C-301A tube is pre- 
ferred for the first detector tube (VI). 
We do not advise the use of dry cell 
tubes for this purpose. The grid con- 
denser (Kl) is the conventional 0.00025 
m. f. with a variable grid leak (GL) of 
the lead pencil mark type. The plate 
voltage is 22.5 volts. 

A two circuit jack (Jl) normally con- 
nects the coupler into the circuit, but 
when the loop plug is inserted the coupler 
is cut out and the loop aerial is auto- 
matically connected directly across the 
condenser (CI). With this arrangement 
it is a simple matter to change from out- 
door aerial to loop and vice versa. For 



14 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



simplicity, the jack can of course be 
omitted. 

The tuning unit or coupler (L1-L2) 
can be a commercial neutrodyne coupler, 
but if home made it is strongly recom- 
mended that the coupler be attached 
permanently to condenser by brass 
brackets as is done with the neutrodyne 
sets. This gives compactness which 
is most desirable in a circuit of this kind. 
Oscillator Circuit 

Here we get into the distinguishing 
feature of the circuit, the circuit which 
produces the oscillations for the hetero- 
dyne effect. The inductance (L3) con- 
sists of two 25-turn honeycomb coils 
placed close together with a tap (a) 
running out from the mid-connection 
between the coils. They are connected 
in series and care must be taken that 
the turns run in the same direction so 
that they act together and do not "buck." 
Across the outer ends of the two coils 
is the variable vernier condenser (C2) 
with a capacity of 0.001 m. f. (43 plate). 
One of the outer ends of the inductance 
is connected to the fixed condenser (K2) 
which has a capacity equal to 0.5 m. f. 
or slightly greater. 

The tube (V2) is an amplifier tube of 
the UV-201A type, or even better, a 
Western Electric 216A. A separate "B" 
battery (B2) is used for this circuit with 
a voltage approximating 67 to 90 volts. 
This battery must be entirely inde- 
pendent of the rest of the circuit, hence 
is one of the reasons for the high cost of 
heterodyning. 

At one side of the oscillator induct- 
ances is the coil (L4) which couples the 
oscillator circuit to the tuning circuit. It 
is a coil of about six turns of No. 20 D. 
C. C. magnet wire, and of course is in in- 
ductive relation with the coils (L3). 
Both sets of coils are supported on a 
single fiber tube, and the coils (L3) are 
connected rigidly to the variable con- 
denser (C2) by brass brackets as with the 
neutrodyne coils. This makes a self- 
contained and compact unit which re- 
quires little space and which is easy to 
wire. 

Radio Frequency Circuit 

Coupled to the plate (P) of the first de- 
tector tube (VI) are two stages of radio 
amplification. The two radio frequency 
transformers are of the special long wave 
type already mentioned and should have 
a rated wave length of from 5,000 to 15,- 
000 meters. As these transformers op- 
erate constantly on one wave length the 
requirements are not the same as with 
ordinary types of transformers, since the 
latter are designed to cover as large a 
range of wave lengths as possible. The 
narrower the band of wave lengths, the 
greater will be the amplification of the 
transformers, and without doubt special 
transformers will soon be on the market 
which have this most desirable charac- 
teristic. The radio frequency amplify- 
ing tubes (V3-V4) may be UV-201A or 
C-301A, and should be provided with 
rheostats of sufficient resistance to per- 
mit of operation on a six volt storage 
battery. A potentiometer (PO) controls 
the grid potential of (V3) 

It will be noted that the radio stages 
are coupled to the first detector tube 



(VI) through tuned coils (L5) and (L6), 
these coils being so arranged that the 
distance between them can be varied. 
Both (L5) and (L6) are 500 turn honey- 
combs, mounted in a two coil mounting 
for convenience in varying the degree of 
coupling. Across each of these coils are 
the two fixed condensers (K3) and (K4) 
which have a capacity of 0.0005 m. f. 
each. These condensers, which should 
be of the mica dielectric type and ac- 
curately calibrated to the specified capaci- 
ty, can be mounted directly on the coil 
mounting. This adjustment of the coils 
is not critical and is easily performed. 
The secondary of the last radio fre- 
quency transformer is connected in the 
usual manner to the second detector 
tube (V5) through the grid condenser 
(K5) of 0.00025 m. f. capacity and the 
grid leak (GL2). The plate of this sec- 
ond detector tube is connected to the out- 
put jack (J2) and the output binding 
posts(p-p'). The latter affords a means 
of connecting a loud speaker into circuit 
or for hooking on one or two stages of 
audio amplification as may be desired. 
It was considered advisable to discontinue 
the set before the audio stages were add- 
ed for these can be installed at any time 
and by conventional audio amplification 
circuits. We believe, however, that the 
average constructor will have many thrills 
with the set the way it is shown before 
he thinks of adding more stages. 

Precautions and Advice 

As with every other radio frequency 
circuit, there is a strong tendency to feed 
back between stages and to start oscilla- 
tions in the radio frequency tubes which 
will not only reduce their efficiency but 
which may even entirely prevent the 
functioning of the tubes. For this rea- 
son the transformers should be well sep- 
arated, and as a further precaution the 
axis of the transformers should be turned 
at right angles to one another to prevent 
inductive feed backs through stray fields. 
For the same reason, the tubes should 
be well separated from one another and 
from the transformers as well. Placing 
well grounded metal shields between the 
transformers and between the transform- 
ers and tubes will minimize such troubles. 

It is suggested that the grid neutral- 
izing stunt of the neutrodyne be experi- 
mented with on the two R. F. tubes and 
the second condenser; that is, two of the 
small "micro-mikes" used for neutral- 
izing the grid should be connected be- 
tween the grids of tubes (V3), (V4) and 
(V5). I have not yet tried this arrange- 
ment but I believe that it would prove 
helpful even though it might not be quite 
so effective as on the shorter wave- 
lengths. In this event we would have a 
"neutrodyne-super-heterodyne", surely 
enough name to pull it through if nothing 
else. The proposed neutralizing con- 
densers are indicated by dotted lines and 
are given the symbols (NC). 

It is of great importance to keep all wires 
well separated and to prevent running 
wires parallel to one another for any dis- 
tance. The sockets should be raised well 
above the base board to prevent leakage 
strays from taking place, and if possible, 
the sockets should rest on a bakelite 
slab rather than on wood. 



We must next be sure that the coils 
(L3) do not buck each other; or in other 
words, that the turns on both coils run 
in the same direction so that the effect 
is that of a single coil. Coil (L4) can 
be moved back and forth until the maxi- 
mum effect is had, and when once this 
adjustment is had it can be left without 
further adjustment. 



Government Regulation 

Radio, which for the first time car- 
ried to the continent at large and per- 
haps Europe and Central America, the 
President's message, also carried his rec- 
ommendations for remedial legislation 
on radio. Echoing Secretary Hoover's 
request that the laws affecting radio 
administration enacted in 1912 be re- 
vised, the President personally told con- 
gress that new legislation regulating radio 
interference is needed. At present, Sec- 
retary Hoover is operating under a sort 
of "gentlemen's agreement" between 
commercial, governmental, private and 
amateur interests, reached last spring 
during the second National Radio Con- 
ference. 

Secretary Hoover stated recently that 
Representative White, who fathered 
the bill which bore his name last session, 
will introduce a simplified radio bill this 
session. The old bill, it is understood, 
has been reduced to first terms so as to 
permit of proper interpretation with the 
development of the art and to give the 
Secretary of Commerce and his advisory 
committee liberal and more or less elas- 
tic authority over the control of national 
radio problems. A recent conference 
between representatives of the govern- 
ment departments was successful in 
eliminating such points of disagreement 
as existed heretofore, and the resultant 
bill was ready to be introduced in the 
house before the end of this month. 

According to Secretary Hoover, the 
radio interference situation today is far 
better than it was at the time the origi- 
nal White Bill passed the house last 
year, due chiefly to the elimination of in- 
terference through the voluntary co-op- 
eration of the several interests. There 
is now little interference between the 
existing broadcasting stations, which are 
decreasing in numbers. 

In general, the President also indorsed 
the enactment into law of the approved 
plan of the Joint Committee on the re- 
organization of the government depart- 
ments, which places radio under the di- 
rection of an Assistant Secretary of Com- 
munications, who would have charge of 
telephone and telegraphs. The post of- 
fice and the radio section of the Bureau of 
Navigation of the Department of Com- 
merce would become a part of the De- 
partment of Communications, according 
to the present plan of the Joint Com- 
mittee. 

Before the reorganization is effected, 
however, all phases of the radio question 
will probably have been threshed out and 
its administration may or may not be tak- 
en away from the Department of Com- 
merce. The proposed bill, it is under- 
stood, carries no suggestion of a transfer 
of radio to the new Communication De- 
partment. 



RADIO AGE — "THE MAGAZINE OF THE HOUR" 



15 



Construction of the Push Pull Amplifier 

By FRANK D. PEARNE 



THE use of the third step of audio 
frequency amplification in most any 
of the standard sets in use today 
results in distortion of the signal and 
considerable noise, so much noise, in fact, 
that the added volume to the signal is of 
little or no value. These noises are 
caused usually by the ordinary tube 
noises in the detector being amplified at 
the same time the signal is amplified. 
Even the second stage will sometimes 
magnify these tube noises to such an 
extent that they are extremely disagree- 
able. 

If, however, the user would get away 
from the conventional idea that a trans- 
former of high ratio should be used in the 
first step, this effect would be consider- 
ably reduced. In code reception, more 
or less distortion does not interfere much 
with the reception, but when listening to 
a good musical selection it makes all the 
difference in the world. It is a well- 
known fact that the lower the ratio of the 
transformers used in audio frequency 
amplification, the less will be the distor- 
tion. As each succeeding stage amplifies 
everything which precedes it, it is only 
reasonable to expect that if the first 
stage has a high ratio of amplification and 
some distortion, that distortion is bound 
to be amplified in each succeeding stage. 

Reversing the Ratios 

Therefore, the order of things should 
be reversed, using the low ratio trans- 
formers in the first stages and the higher 
ratio in the last. This arrangement 
would cause the first stages to be ampli- 
fied without distortion, after which it 
could be stepped up in the higher ratio, 
with only the distortion of the last stage 
affecting the loud speaker. 

To eliminate the distortion in the last 
stage and at the same time increase the 
volume to such an extent that it may be 
heard two or three city blocks from the 
receiver, the "push pull" amplifier should 
be used in the last stage. Until recently, 
this type of amplification was out of the 
reach of the broadcast listener, because 
the special transformers required in its 
construction were not available. How- 
ever, during the last month or two, 
transformer manufacturers have dis- 
covered that there is a great field for this 
product, and it is now possible to get 
these special transformers made by most 
all of the reliable manufacturers. 

This type of amplifier will produce 
undistorted signals of enormous volume, 
providing that the signals presented to it 
are of good intensity and are clear. It 
is generally used as a third stage, but 
owing to its great amplifying power it 
can be used quite successfully in the 
second stage if desired. 

Connection With Phones 

By looking over the accompanying 
drawing one will notice that the direct 
current of the plate battery is not applied 
to the phones, as the secondary of the 



SPECIAL AFT 




Figure 2. 



output transformer is directly connected 
to them. This greatly aids in obtaining 
clear reception, as the plate battery 
noises are eliminated in the phone cir- 
cuit. The parts may be either mounted 
in a cabinet, or on a bakelite panel which 
will lie flat upon the table. The latter 
arrangement can be made into a very 
neat appearing outfit, if carefully wired 
with the parts properly located. 

The material required for its construc- 
tion consists of the following parts, two 
push pull transformers, one rheostat, 
two sockets, two amplifying tubes, one 
C battery, twelve feet of bus bar tinned 
copper wire, No. 14, eight binding posts, 
one bakelite panel, 7 by 10 by 3-16 inches, 
and four rubber feet. 

The resistance of the rheostat will 
depend upon the type of tubes used. 
The best tubes for the purpose are the 
W. E. 216 A and if these are used the 
rheostat resistance should be approxi- 
mately 6 1-2 ohms. These tubes are, 
however, hard to get. The UV-201-A 
tubes may be substituted in which case, 
a 25 ohm rheostat should be used. 

Making the C Battery 

The C battery may be made of flash- 
light battery cells and the voltage re- 
quired will depend upon the plate bat- 
tery voltage used. The pressure of one 
of these flashlight cells is about 1 1-2 
volts and for a 90-volt plate battery, 
three cells will be sufficient, but if more 
pressure is used in the plate circuit, the 
number of cells in the C battery should 
be increased. 

In connecting the C battery in the 
circuit, care must be used to see that the 
negative terminal of the cells is connected 
to the center tap, or the extra binding 
post on the input transformer. This 
puts a negative bias on the grids of the 
two tubes and if the connections are 
reversed, the amplifier will not work. 
The No. 14 tinned copper wire is to be 
used in wiring up the set and any connec- 
tions which are not made on the binding 
posts direct, should be carefully soldered 
to insure perfect contact. 

All parts may be fastened to the panel 



by means of small brass machine screws 
and nuts and the rubber feet are to be 
fastened, one under each corner, so that 
the panel will be raised slightly from the 
table and the entire weight of the ampli- 
fier will come on the rubber feet. 

The greatest care must also be exer- 
cised in the wiring. The radio fre- 
quency wires which are the plate and grid 
wires must be widely separated and, in 
fact, it is a good idea to keep the grid 
wiring as far as possible from any of the 
other conductors. If this is not done, 
there may be an audio frequency feed 
back to the grids, by induction between 
the wires, which will cause the amplifier 
to howl. 

Results Are Surprising 

If these instructions are carefully fol- 
lowed, the result of this addition to any 
set will be surprising. It may be found 
that using it as a third stage will give 
entirely too much volume in the ordinary 
home, as it will be almost deafening, but 
will still retain the quality which is found 
in the lower stages. In this case it can 
be substituted for the second stage. 
Even if the push pull is used as a first 
stage amplifier, the results will be much 
better than the ordinary one stage am- 
plifier and the music will come in so clear 
and distinct that one would almost be- 
lieve the player was in the same room. 

After using such an arrangement it 
will be hard to ever go back to the ordi- 
nary method of audio frequency ampli- 
fication. It must be understood, how- 
ever, that this type of amplifier will not 
remedy poor reception, that is, if the 
receiver does not bring in clear, distinct 
signals, the amplifier will only repeat 
what is fed into the input transformer, 
but with a good receiver, nothing can 
compare with the results obtained by 
using this arrangement. 

On the next page will be found an isometric 
drawing, showing in [detail the method of 
assembling the Push Pull amplifier. Read- 
ers write to us saying these picture diagrams 
are more easily read than photographic 
illustrations. — The Editor. 



16 



RADIO AGE— "THE MAGAZINE OP THE HOUR" 




RADIO AGE— "THE MAGAZINE OF THE HOUR" 



17 



The Rosenbloom Circuit 



ONE of the greatest difficulties in the 
construction of a radio set which 
some beginners encounter, is the 
soldering of the connections and for those 
who cannot do a good job of soldering, the 
Rosenbloom circuit offers an easy way 
out. This arrangement was designed by 
William Rosenbloom, of Revere, Mass., 
and has so few connections that practic- 
ally all of them can be made on the bind- 
ing posts alone. It is very efficient and 
has very few controls compared to most 
of the other good sets in use today. 

Comments on the circuit, made by 
those who have used it, are quite favor- 
able, some claiming that for selectivity 
and sensitiveness, especially when using 
a UV-200 detector tube, it can not be 
excelled. Because of the few parts used 
in its construction, one man was able 
to assemble a test circuit and had it work- 
ing in less than one hour. No vario- 
coupler is used which, of course, will dis- 
pense with many soldered joints on the 
necessary contacts and the substitution 
of a variometer in the primary circuit 
in combination with a fixed condenser 
gives extremely sharp tuning with only 
one control. 

The two variometers should be of the 
basket-ball type to get the closest tun- 
ing, although any of the standard wood, 
or bakelite variometers will work, but 
the builder is advised to select those 
having the least distributed capacity. 

Condenser 

The condenser used in the aerial cir- 
cuit is a fixed Micon condenser having a 
capacity of .0005 M. F. which is equal to 
that of a 23-plate variable, although 
not adjustable. The variable is not 
needed here because of the fine tuning 
qualities of the variocoupler in this par- 
ticular part of the circuit. In some 
cases a small 3-plate variable has been 
shunted across the terminals of this 
condenser to give a vernier effect, but 
this is not necessary under ordinary con- 
ditions. 

It will be noticed that the drawing 
shows a potentiometer connected across 
the filament battery leads. The lever 
of this potentiometer is connected in 
series with the phones and the plate bat- 
tery for the purpose of adjusting the volt- 
age in the plate circuit. This also may 
be eliminated if desired, but when tun- 
ing in a weak wave coming from a long dis- 
tance, it is wonderfully effective, and as 
Mr. Rosenbloom says, "if anyone doubts 
its value, he should use the receiver for 
awhile, with the potentiometer, and then 
attempt to do long-distance work without 
it. 

Perhaps one of the reasons that some 
amateurs are so successful in getting 
long-distance reception and others are 
not, is due to the fact that some use the 
potentiometer and others do not. It is 
one of the most important controls on 
any receiver, because there is one certain 
voltage at which the plate circuit will 
function best, although some results may 



By FRANK D. PEARNE 



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GRID LEAK 1 MBSOtiM 
GUlD CONDENSER . OOO 25 



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be obtained with voltages somewhere 
near this critical point, but for the ideal 
reception, it should be exact and the po- 
tentiometer furnishes the means of getting 
this fine adjustment. 

The other variometer serves to tune the 
plate circuit, thus making the circuit 
regenerative. This regeneration takes 
place through the tube itself, the plate 
and grid, acting as a small condenser, 
through which any change in the plate 




Old Favorites 

Fans who have been experiment- 
ing with various circuits have 
begun to show a definite trend 
back to hook-ups which they tried out 
months ago and then laid them aside 
to try something "new." This sug- 
gests the comment that there are only 
a limited number of fundamental 
radio hook-ups and that changes in 
these circuits are often changes for 
the worse. One of the interesting 
circuits that did well for those who 
tried it some months ago is the 
Rosenbloom. A full page isometric 
drawing is printed on the next page, 
showing how to assemble this re- 
ceiver. — The Editor. 



circuit will react upon the grid, building 
up the charge upon it, causing the origi- 
nal charge to be sustained for a longer 
period and giving considerable additional 
amplification to the signal. The fine 
gradations of control made possible by 
the potentiometer are especially evident 
when the gassy UV-200 detector tube is 
used. 



Ground Wire 

When the parts are mounted on the 
panel as shown in the drawing, one should 
make sure to so connect the variometer 
which is used in the primary, in such a 
way that the ground wire will be con- 
nected to the end of the rotor shaft 
which extends through the panels, as 
this will greatly reduce the body capaci- 
ty effect. The plate battery should be 
of the variable type having taps at dif- 
ferent voltages, so that any voltage from 
16 to 22 1-2 may be obtained. 

The condenser which is shown con- 
nected across the phones is a mica type 
fixed condenser having a capacity of .001 
M. F. Some arrangement for switching 
off the filament battery should be used, 
as the potentiometer, which although 
having a high resistance of 200 ohms will 
run the battery down in time, for the 
reason that a very small amount of cur- 
rent will flow through it all the time, 
whether the set is in use or not, if some 
switch is not used in the battery circuit, 
to open it when the set is not in use. 
The same end, however, may be accom- 
plished by disconnecting one of the bat- 
tery terminals when the set is not in use. 

The rheostat used is the standard 
6 1-2 ohm type, which is always used with 
the UV-200 tube. The grid leak has a 
resistance of from 1 to 1 1-2 megohms 
and the grid condenser has a capacity 
of .00025 M. F. If any tube other than 
the UV-200 is used, the grid leak should 
be variable. 

The amateur will find this circuit to 
be one of the most simple arrangements 
that can be constructed and he will not 
be disappointed with the results if the 
instructions are carefully followed. 



18 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



fry. 




RADIO AGE— "THE MAGAZINE OF THE HOUR' 



19 



Pickups by Readers 



WITH this issue we leave behind 
us a year's accumulation of new 
reception records, and challenges, 
and enter upon an effort to pile up the 
best record for the new year. 

As we look over the mass of letters 
from the many Pickup fans while rever- 
ently filing them away, we are filled with 
a feeling of satisfaction that our radio 
brothers have accomplished much, and 
turning our thoughts toward the future, 
we wonder what the many readers of this 
department will accomplish in the coming 
year. We wonder what kind of receiver 
will do the most consistent work in get- 
ting the DX stations, and we wonder 
when the Pickup fans will stop breaking 
records. 

We know, fellows, we are in for some 
keen surprises, and we know that this 
is going to be one of the big depart- 
ments of RADIO AGE. Half the fun 
in radio is building a set from clear in- 
structions, and the other half is telling 
the other fellow about what the set can 
do. 

If you want to tell it to a real bunch 
of radio fans, send in the dope to the 
Pickups By Readers department, and 
you may be sure that it gets before the 
kind of fellows who appreciate it. 

C'mon BCL's, we're off on a flying 
start to set new records, and as we fire the 
starting gun, we simultaneously wish 
you a HAPPY AND LONG-DISTANCE 
BREAKING NEW YEAR! 

THE PICKUPS EDITOR. 



It looks pretty much like the Kop- 
prasch fans have a flying start on the 
rest of the contenders from the appear- 
ance of the letters following: 

1305 Dayton Ave. 
Springfield, Ohio. 
RADIO AGE, 

Pickups Department, 
Gentlemen: 

I am writing you to let you know as to 
the nature of results I am getting from 
the Kopprasch circuit published in the 
April issue of RADIO AGE. 

It is, and is doing all you claim for it. 
We have stations here within a radius 
of fifty to seventy miles, but they don't 
come in as strong as the stations two 
hundred to one thousand miles distant. 

I held WGY last Thursday night for 
three hours and forty-five minutes with- 
out one bit of fading, and can pick up 
WOR, WFAA, WBAP, NAA, KSD, 
CFCA, WDAJ and many other stations 
at will. It is the best circuit I have ever 
tried out, and I speak from costly ex- 
perience, having had twenty-one of them. 
The Kopprasch is the bearcat of them all. 
Long distance stations come in good and 
strong, and I think considering that my 
location is one far from favorable, that 
I have been getting results. 

For reception, my antenna is between 

two tall chimneys and only two wires 

thirty-six feet long. Tell Mr. Kopprasch 

that his circuit is certainlv a humdinger. 

CHARLES H. MOORE. 

Mr. Moore uses a one-tube set. His 
letter really calls for no comment, but 
will probably arouse the interest of many 
other BCL's who are using other cir- 
cuits. 



KOPPRASCH CIRCUIT FOR W-D-ll TUBES. 



GRID LEAK 




6- BATTERY 
22 y 2 VOLTS. 

FIGURE 1. 



MOUNTING OF VARIOMETERS AND TUBE 

VARIOMETER^ VARIOMETER^ 





/' 




\ 


TUBE 


/ 




\ 












10 o ® ' 

1 


i <b yj <S> 






\ 

\ 
s 




/ 
/ 




-\ 




' / 

/ 












i I... -i 




I 











Figure 1. This shows the Kopprasch circuit and the method of mounting the inductance 
between the two variometers. The inductance consists of forty turns of No. 22 DCC, with 
taps at every eighth turn, and is wound in opposite direction to the stators of the var- 
iometers. Care should be observed that the stators are wound in the same direction. Full 
details concerning this set appeared in the April 1923 issue of Radio Age. 



Hear number two from another fan 
using a Kopprasch: 

2111 St. Paul Street 
Baltimore, Md. 
RADIO AGE, 

Pickups Department, 
Gentlemen: 

In answer to G. W. Jeffers, of New 
Jersey, in the November Pickups Depart- 
ment, I would venture that if Mr. 
Jeffers keeps going at the rate he has been 
traveling, he can open the window, and 
get CHILE. And he did it with his 
little Kopprasch. Let me explain. 

With my Kopprasch, built last April, 
with the WD11 tube using 16J4 volts 
on the plate, I have been able to pile 
up the following record, some of the work 
being done during violent electrical 
storms. 

I have twenty-eight stations to my 



credit, with letters in each case to prove 
it. I hold as the following my best 
reception: WOS, WOC, WDAP, and I 
respectfully beg to ask you to remember 
that Baltimore is considered a dead spot 
for radio signals, so you will please 
take this into consideration. I am almost 
afraid to venture to say what it will 
do with two stages of AF! My best 
distance may only be 800 miles, but I 
don't believe that any other circuit 
could do even that much in this town. 

I hear MacMillan getting messages 
from WJAZ regularly, as Chicago is 
one of our standbys. Put me down as 
a Kopprasch booster. 

Very truly yours, 

JOHN J. DRECHSLER. 

The Kopprasch circuit seems to have 
a queer habit of working in long jumps. 
breaking rules regarding dead spots, 



20 



RADIO AGE — "THE MAGAZINE OP THE HOUR' 



The foregoing letters speak pretty well 
for this circuit. In a postscript, Mr. 
Drechsler says, "I can tune anything 
out that I want to." You fellows who 
have been having trouble with your sets, 
dig up that April issue and get posted 
on this circuit. 



/I&Q//91 



The users of Cockaday sets are by no 
means back-numbers this month. Those 
using this circuit are getting a great kick 
out of the long distance range it affords 
as the following will explain: 

Madison, Wis. 
RADIO AGE, 

Pickups Department, 
Gentlemen: 

I have read several numbers of your 
journal with considerable interest. I 
am the enthusiastic owner of a Cockaday 
Four Circuit Tuner and have read the 
letters in your last issue as sent by 
others using the set. Last year I used 
a regular Armstrong regenerative set 
with a variocoupler and two vario- 
meters. During my vacation last summer 
I had time to read up on the newer 
circuits in the radio journals and read 
the description of the set in RADIO 
AGE and how to build it. Have had it 
working since September 16. I can 
heartily endorse all other users have said 
about the set and think I have some 
pretty good records myself. 

My set was constructed from parts 
in the old set with the necessary addition- 
al parts. It has the regular arrange- 
ment with two stages of audio frequency 
amplification. Last year I had 137 
stations on my map of North America 
and since setting up the Cockaday set 
have added thirty-five making 172 that 
have been heard in less than twelve 
months as I put in my last year's set 
at Christmas time. I have heard about 
125 of the 172 stations this fall with the 
Cockaday set and can get easily fifteen 
to twenty stations any evening if I 
want to stay with it. The best record 
I have made was on October 20, when 
I heard the following stations from 7:30 
until 11 :20 p. m.: 
WOC Davenport, Iowa 
WHA Madison, Wis. 
KFIC Fond du Lac, Wis. 
WDAP Chicago, 111. 
WDAF Kansas City, Mo. 
WBAP Fort Worth, Texas 
WDAO Dallas, Texas 
WMAQ Chicago, 111. 
KYW Chicago, 111. 
WHAS Louisville, Ky. 
KDKA East Pittsburgh, Pa. 
WGR Buffalo, N. Y. 
WEAH Wichita, Kans. 
WOQ Kansas City, Mo. 
WHN Ridge wood, N. Y. 
WTAM Cleveland, Ohio 
WLAG Minneapolis, Minn. 
WOAW Omaha, Neb. 
WSB Atlanta, Ga. 
WBAK Harrisburg, Pa. 
WSAI Cincinnati, Ohio 
9XM Madison, Wis. 
KFKB Milford, Kan. 
KFI Los Angeles, Calif. 

KGO Altadena, Calif. 

The above list of twenty-five stations 
covers almost the entire length of wave 
ranges, except KSD, and I have heard 
them often so the set has plenty of 
range, and covers most of the United 
States and Canada, as I have heard six 
Canadian stations from Calgary to 
Montreal. 

Its freedom from body capacity, sharp 
tuning and loudness are a joy to every 




22fk 



6&Q0AU7 



Figure 2. This shows the connections of the first tube set, 
readers have accomplished long distance records. 



with which several of our 



one. My set brings in all of the stations 
of 500 watts and over on a loud speaker 
in my 500 mile radius, and KDKA, 
WGY, WOR, WJZ, WSB, WFAA, 
WBAP and KLZ as well. 

The letters from the fans with the 
different sets are very interesting. KEEP 
IT UP. 

Yours very truly, 
WILLIAM H. WRIGHT. 

Associate Professor of Agricultural 
Bacteriology, University of Wisconsin. 

There "ain't" no bacteria on the Cock- 
aday, is there, professor? The fellow 
who puts in a Cockaday gets blisters on 
his fingers from holding the pencil in his 
hand all the time to log the many stations 
he hears. And what's more, the fellow 
who uses a four-circuit tuner doesn't let 
any grass grow under his feet when it 
come? to getting the long distance stuff. 



Memphis, Tenn. 
RADIO AGE, 

Pickups Department, 
Gentlemen: 

Just a little line to let you know that 
on the evening of November 27 I picked 
up WTAS, Elgin, 111., and WCAS, 
Minneapolis, Minn., over a friend's 
Cockaday. I believe that this is a record 
for a station of small power, with WMC, 
my local station, going full blast. 
Very truly yours, 

JAMES P. COOPER. 

The above letter is just one of many 
we receive, praising the selectivity of the 
Cockaday set. 



The following communication is just 
another reason why we said that the 
Kopprasch fellows have a flying start: 
242 Vine Street, Council Bluffs, Iowa. 
RADIO AGE, 

Pickups By Readers Department. 
Gentlemen: 

I noticed in your reference to Mr. 
Fleckenstein's list of stations in your 
November issue, that you want to know 
how about the Kopprasch fellows. Well, 
here i9 from one of them and I kind of 



think I have him beat. Here is my list 
for November only: Stations WJAZ 
WHB, WLAN, WGY, WAAG, 
WDAF, WOS, WDAG, WSAP, WLAG, 
PWX, WDAP, WFAA, KPO, WAAF, 
WOAI, WCK, WHAS, WSB, WCAS, 
WCAH, KSD, KDKA, WPAL, WLW, 
WOAA, KLZ, KFI, WAAK, WWJ, 
WJAX, KYW, WPAD, WWI, WKY, 
WTAM, WEAH, WOC, WLAJ, WJAD, 
WOO, KWH, WGR, WMAQ, WEAF, 
KHJ, WBAH, WHA, WSAI, WJAS, 
WRM, WGAY, WCX, WMC, WKAA, 
WCAM, KFKA, WFY, WPAH, WBAP, 
WCBD, CKCK, KGW, WTAS, KSS, 
WNAP. The above list was logged just 
as received, and does not include out- 
local stations WOAW and WAAW, two 
very powerful stations which I succeeded 
in tuning out a number of times, and 
when you can tune out either one of 
them, you are going some, as they are 
only four miles off. While I am writing 
this, I am listening to a very nice concert 
from WDAP, Chicago. 

It may help some of the Kopprasch 
boys if they will add a 43-plate variable 
condenser in series with the antenna, 
hook up stator to antenna and rotor 
to antenna binding post on set; find it 
helps a great deal with my three WD 11 
tube Kopprasch receiver. From the 
other lists that have been published, I 
think the Kopprasch is holding its own 
pretty well; one station I overlooked in 
my list is CFCN, Calgary, Alberta, 
Canada. I had them for a short time 
but was cut out by another station. 
Respectfully, 

R. L. SHEWARD. 

It looks like we misjudged these Kop- 
prasch fellows! While the other fellows 
were busy writing about how many long 
distance stations their sets could receive, 
the Kopprasch users were evidently busy 
tuning in a few extra ones to make their 
lists overlap the rest. That's SOME 
list, if you ask us. 



R. R. O. Box 118, Indianapolis. 
RADIO AGE, 

Pickups by Readers Department. 
{Continued on page 44.) 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



21 












DON'T ANNOY YOUR NEIGHBORS 

Photo at left shows that you should not put too high a plate voltage on the detector tube. If you do, it not only 
spoils the quality of the radio music but it also makes it impossible to tune your set without causing squeals. 

Photo on right shows that you should not turn the rheostat that controls your tube on too full. This will dis- 
tort the music and cause squeals. It will also greatly shorten the life of your vacuum tube. Don't turn the dial that 
controls regeneration around too far. The proper place to stop is just before the squealing point. If you go beyond 
that point the squeals that you will hear will also be heard by everyone in your neighborhood. (Kadel & Herbert 
Fotos.) 



Cause of Fading 

When radio first was used for long dis- 
tance communication it was noticed that 
signals were not transmitted as far during 
the day as during the night time. It has 
also been observed that at night radio 
signals on the higher radio frequencies 
or shorter wave lengths vary greatly in 
intensity from minute to minute. Per- 
sons who receive broadcast concerts from 
distant stations have occasion to notice 
this variation in intensity of received sig- 
nals since loud signals may be received 
from a given distant station at one mo- 
ment only to disappear entirely for a few 
minutes and then recover their original 
intensity. 

This and related phenomena have been 
recorded from time to time and various 
hypotheses have been brought forward 
in an attempt to explain them. The phe- 
nomena are dependent upon a large num- 
ber of variable quantities such as the 
weather conditions, the nature of the 
country over which transmission occurs, 
the surroundings of the transmitting and 
receiving stations, and the method of 
handling the receiving apparatus. Only 
by a statistical study in which the re- 
sults obtained simultaneously at a large 
number of receiving stations are collected 
and tabulated, may reliable averages be 
obtained. 

In an attempt to secure some worth- 
while statistics of this kind, a co-operative 
study of radio signal fading was made by 
the Bureau of Standards and the Amer- 
ican Radio Relay League during 1920 
and 1921. In these tests from five to ten 
radio stations transmitted signals in suc- 
cession on certain nights, according to 



prearranged schedules. The signals were 
received simultaneously by about one 
hundred receiving stations whose op- 
erators were provided with forms for re- 
cording the variations in the intensity of 
the signals as received. 

The paper gives summary tables point- 
ing out possible relationships between 
weather conditions and the fading and in- 
tensity of radio signals and the prevalence 
of strays or atmospheric disturbances. 
On account of the limited number of ob- 
servations and the large number of fac- 




The squeals and howls being sent 
through the air every night by owners 
of single circuit regenerative sets and 
other trick circuits is fast making it 
impossible to enjoy listening to radio 
concerts. If the owners of radio sets 
that cause squeals would operate 
their sets correctly they would not be 
spoiling their neighbors' concerts 
every night. Photo shows proper 
type grid leak. This is very im- 
portant. (Kadel & Herbert Foto.) 



tors which influence transmission, the 
statistical results can be considered as 
only tentative. 

The general result of these tests, how- 
ever, substantiates the theory that the 
sources or causes of fading are intimately 
associated with the conditions at the 
Heaviside surface, which is a conducting 
surface some sixty miles above the earth. 
Daytime transmission is largely carried 
on by means of waves moving along the 
ground, while night transmission, espe- 
cially for great distances and short waves 
is by means of waves transmitted along 
the Heaviside surface. Waves at night 
are thus free from the absorption en- 
countered in the daytime but are subject 
to great variations caused by irregulari- 
ties of the ionized air at or near the Heavi- 
side surface. These variations probably 
account for fading. 

The results of these tests are em- 
bodied in Scientific Paper No. 476 of the 
Bureau of Standards. Copies can be ob- 
tained from the Superintendent of Docu- 
ments, Government Printing Office, 
Washington, D. C. The price is ten cents, 

New St. Paul Studio 

St. Paul made its debut as a permanent 
radio broadcasting station on December 
12 with the initial program from the 
new studio just completed in the St. 
Paul Athletic Club. 

Regular programs are broadcast al- 
ternately with those from Minneapolis 
over WLAG, the Twin City Radio Cen- 
tral, operated by the Cutting & Wash- 
ington Radio Corp., in Minneapolis, the 
St. Paul studio becoming a permanent 
unit of WLAG. 



22 



RADIO AGE — "THE MAGAZINE OF THE HOUR' 



Radio's Great Future Forecast 




Two points impressed themselves upon observers at the second annual Chicago Radio Show, held in the Chicago 
Coliseum, November 20 to 25. One was the tremendous attendance and the other was the eagerness of the throngs 

to get radio information. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



At Chicago's Recent Exhibition 



: 





The 1922 radio show crowd was about sixty per cent boys. The 1923 crowd was much greater and was only about 
twenty per cent juveniles. The older people have taken up the art in earnest and that is one of the reasons for 

the increasing stability of the industry. 



24 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



Simple Experiments With Radio Control 



By CARL MASSON 



THOUGH the Scientists of the world 
have presented us with many 
wonders in connection with radio, 
the speed at which new inventions are 
appearing, reveals that there are still 
greater wonders in store for us, pertain- 
ing to this branch of science. 

Manless vehicles, boats, airships, etc., 
made possible by radio, have recently 
startled the world. Radio control will, 
no doubt, be an important factor, in the 
near future. 

Bearing this in mind, the author pre- 
sents a group of interesting experiments 
for the amateur. Realizing that the av- 
erage amateur has but a scanty work- 
shop, the author has endeavored to make 
these experiments as simple as possible. 
k— In radio control, it is necessary to have 
some sort of a relay which will respond 
to ,'adio waves, at the will of the oper- 
ator. Recently, much has been done to 
develop such a relay, but due to compli- 
cated parts involved^ in them, amateur 
experimenters have left this use for radio 



Fi 3 V 



The R&oeiver. 



N7 



m 



oc X- C=X=X z pi 



Grturvi 



c 




«e|ay 



8 



F,}.*-. 


Assembly of Coherer 
0.n<£ de coherer- 






Ooubie B' 
pop. 


' J _ Class Tube 






CO 


r "~m i Oi 


•— \_/-- 


i3 F! ""3S- Co f^ Y Rod- 




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untouched. 

Recalling the pioneer days of "wireless" 
(as it was then called) Marconi's coherer 
and decoherer suggests a simple relay 
circuit which might be applied to experi- 
ments with radio control. 

Fig. 1 shows such a circuit. Since co- 
herers and decoherers have entirely dis- 
appeared from the market, perhaps it 
would be best to describe how to construct 
them. 

To make the coherer, get a piece of 
glass tubing, 2" long, and about 1/4" in 
diameter, also 2 double binding posts, 
and 2 pieces of copper or brass bar about 
2 1/2" long and which will fit the glass 
tube quite snugly. Fig. 2 shows the as- 
sembly which is self-explanatory. Be- 
tween the copper bars, which slip within 
the glass tube, is a quantity of metal fil- 
ings, (preferably silver) filling the gap, 
which should be about 1/8 inch. 

Now, when -the radio waves pass 
through the coherer, they cause the fli- 
ngs to cohere — that is, stick together, 



allowing the current to pass and oper- 
ating the relay. But when once the fil- 
ings have cohered, they will remain so, 
unless some means is provided to deco- 
here them. Hence an electric bell is 
placed in the circuit as shown in Fig. 1. 
When the relay allows the current to 
pass, the bell will ring, and the hammer 
will tap the glass tube, causing the filings 
to decohere. An ordinary telegraph re- 
lay is used. 

Since these experiments are conducted 
indoors, a small single wire antenna, 
about 8 feet long, is sufficient. Gas or 
water pipes serve as grounds. 

Now for the transmitter by which the 
control is possible. The circuit is noth- 
ing other than that of a simple spark coil 
sending set. A 1/8 inch coil is sufficient. 
Fig. 3 shows the circuit. An antenna of 
about 8 feet is also used in the transmit- 
ter. 

For the first experiment, connect a toy 
electric motor in the receiving circuit 
(Continued on page 36.) 



W 



The Jrams twitter 



StxwrKGcLp 



-I!" 



SecowcLuy 



Primary J, 



S. 



Hil'lt- 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



25 



Substitution of a Tube for a Crystal in a 
Selective Crystal Detector Circuit 



THE construction of a circuit using 
a crystal detector, as offered in the 
December issue of RADIO AGE, 
forms the basis of a progressive circuit 
in which we are now showing a tube 
detector. 

The tube is going to be a much more 
sensitive detector and will for that reason 
afford a far greater receiving range. 
Our tuning apparatus must be more 
selective to permit of discriminating 
reception among the many broadcast 
stations. 

It is presumed that the construction 
of variocoupler already given has your 
consideration, although any standard 
type will serve. 

Coupler Modification 

An additional winding is indicated. 
The form can be a cardboard tube 2 1-2 
inches long and four inches in diameter 
for variocoupler of our previous descrip- 
tion, or to equal that of whatever size 
is used. Taking No. 24 double covered, 
cotton wire begin winding at 1-4 inch 
from the end of form, having first 
punched two small holes spaced at 1-4 
inch in parallel to anchor wire by lacing 
through them. 

Wind forty turns firmly and terminate 
with a similar anchorage, leaving leads 
for making connections. Do not coat 
this secondary winding with anything. 
This acts as a deterrent to sharp tuning 
necessary in the secondary circuit (this 



By J. A. CALLANAN 

is not an important matter in the primary 
circuit). 

This completed coil is then placed end 
to end against the rotor of the vario- 
coupler and made secure by means of 
four brass sheet strips cut 1-4 inch wide 
by 1-2 inch long which are used as con- 
nectors, being bolted to the two forms, 
on the inner side for appearance sake. 
This will leave a 3-4 inch space bare 
between the two coils, the tickler coil 
shaft and bearings being in this free 
space and the rotor (tickler) free to 
revolve inside the completed coil. 
Mounting Unit 

The completed unit is mounted in a 
horizontal position and supported by 
three wood blocks as illustrated in 
diagram B. These are placed at either 
end of the unit and between the two coils. 
The unit is mounted 1-2 inch behind the 
panel to avoid body capacity. 

Connections 

Proper connections are of vital import- 
ance to avoid necessity of shielding 
resulting in an appreciable loss of energy. 
We must have as much of the wiring as 
possible at ground potential. 

Connect the antenna lead to the end 
of the primary nearest the secondary 
winding and the grid lead to the end 
of secondary nearest the primary wind- 
ing. 

The terminal of the rotor (tickler) 
which connects to the plate of the detec- 



tor tube should be nearest the primary 
at the maximum dial reading and at 
right angles at zero reading. As this 
is a revolution of only ninety degrees 
the dial need only be graduated through 
one fourth of its circumference. In 
revolving from zero to maximum the 
tickler coil is rotated in a clockwise 
direction. 

Detector Tube 

The detector tube is the heart of the 
circuit; the greater its sensitivity the 
greater the possibilities in receiving 
range. A good, six volt detector tube 
often affords reception more satisfactory 
from the standpoint of signal volume 
and receiving range than a peanut tube 
(toy tube) with one stage of amplifica- 
tion. 

The U V 200 tube with a storage 
battery for filament supply gives the 
best results. However, if the expense 
of storage A battery is at first prohibitive, 
the U V 201A can be operated on dry 
cells, eight connected in series of four, 
two sets in parallel, with much satis- 
faction. Twenty-two and one half 
volts plate potential can be employed 
with either tube, and a maximum of 
45 volts with the U V 201A. 

A .00025mfd fixed grid condenser 

(mica) and a two megohm fixed grid leak 

will serve for either tube cited and should 

be mounted directly to the tube socket, 

(Continued on page 28.) 




Picture diagram showing the electrical connections of the Tube Units 



26 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



How Receiving Tuners Work 



IN THE fifth of his series of radio 
talks delivered through WEAF, 
John V. L. Hogan, consulting engi- 
neer and former president of the Insti- 
tute of Radio Engineers, discussed the 
subject of "How Your Receiving Tuner 
Works." 

His presentations have been given 
most enthusiastic response because of his 
clear and simple presentation. In the 
course of his remarks on December 7, 
Mr. Hogan said: 

"The interval that interests us most is 
from 550 to 1040 kilocycles, for the sta- 
tions using the wave frequencies between 
those limits are powerful enough to be 
heard a good many hundred miles. The 
fifty individual wave frequencies in this 
range were chosen at separations of ten 
kilocycles because any two waves whose 
frequencies differ from each other by that 
amount should not overlap or produce 
direct interference with each other in a 
good radio receiver. To understand just 
why this is so we must think for a few 
moments about what goes on inside a 
radio receiving tuner. 

"Let us begin by noting that at this 
very moment there are two powerful 
broadcasting stations in New York City 
sending out streams of radio waves. 
One of these is WEAF, where I am talk- 
ing, and the other is WJZ. The waves 
from WEAF are of 610 kilocycles fre- 
quency; when they reach your receiving 
aerial, a tiny fraction of. a second after 
they leave here, they generate electro- 
motive forces of 610 kilocycles frequency 
on your receiving aerial wires. Those 
electromotive forces, as you would have 
guessed from their name, if you did not 
already know, are simply forces that tend 
to move electrons (or electric current) 
in the circuit where they are generated. 
Thus, whenever WEAF is sending, its 
radio waves are doing their best to pro- 
duce electric currents of 610 kilocycles fre- 
quency in your receiving antenna system. 
In the same way, the waves from station 
WJZ are trying to generate electric cur- 
rents of 660 kilocycles frequency in your 
receiver, for 660 kilocycles is the wave 
frequency of that station. 

"Now suppose that you are anxious to 
hear the transmission from this station, 
WEAF, without hearing anything what- 
ever from WJZ. What must you do? 
The answer is perfectly simple; it is only 
necessary for you to permit the WEAF 
waves to produce a strong 610 kilocycle 
current in your receiver while at the same 
time preventing the WJZ waves from 
generating any appreciable current in 
your set. To hear WJZ without inter- 
ference from WEAF you would do the 
opposite of that, or develop the greatest 
660 kilocycle current you could while 
suppressing the 610 kilocycle currents. 

"Of course, this raises another ques- 
tion. How can you encourage waves 
of one frequency to generate strong cur- 
rents In your aerial-to-ground or your 
loop antenna circuit and at the same time 



By JOHN V. L. HOGAN 

discourage the waves of all other fre- 
quencies? The answer to that lies in 
electrical tuning, and our next job is to 
get some idea of how tuning is done. 

"You know that practically all receiv- 
ing sets contain condensers and coils of 
wire. Sometimes the condensers are of 
a certain fixed size, and sometimes they 
are variable, but without some sort of 
condenser a radio receiving set won't do 
much in the way of tuning or'selecting 
between waves of different frequencies. 
So, too, with the coils of wire. These 
are generally called inductances, or (to 
speak correctly) inductors. Sometimes 
the inductors are fixed in size and posi- 
tion; sometimes they are variable by 
means of switches or as in variometers, 
so that their effective values may be 
changed at will. 

"Did you ever wonder why these 
condensers and inductors are used in 
radio receivers? It is because an elec- 
trical circuit that is made up of such a 
coil and a condenser is capable of being 
tuned to resonate to or select alternating 
currents of any particular frequency one 
may desire. Electric condensers possess 
the electrical property called capaci- 
tance; inductors have the electrical 
property called inductance. An electri- 
cal circuit that contains both capacitance 
and inductance always is capable of 
passing more electric current of some one 
frequency than of any other frequency, 
for the same amount of generating or 
electro-motive force. What particular 
frequency in cycles or in kilocycles per 
second get through best, depends upon 
the amount of capacitance and induc- 
tance in the circuit. Thus, by changing 
the amount of capacitance (as you can 
do by means of a variable condenser) or 
the amount of inductance (as you can 
with a tapped coil or a variometer) you 
can change the frequency to which the 
circuit is most responsive. This is what 
you do when you adjust the control 
knobs of your receiver. The act of tun- 
ing is simply making the inductance and 
capacitance (or the coil and condenser) 
values of your receiving circuit correct 
for the production of the greatest amount 
of current of the frequency you desire to 
receive. Right now your receiving sets 
are adjusted to respond strongly to the 
610 kilocycle currents generated by the 
610 kilocycle waves that WEAF sends 
out. 

"Perhaps this will be still clearer to 
you if we consider for a moment how 
very much radio tuning is like musical 
tuning. A piano string has a certain 
mass, which in mechanics is very much 
like inductance in electricity. The 
string also has a certain flexibility or 
flimsiness or looseness, which is mechan- 
ically the analogue of capacitance in 
electrical circuits. If we vary the mass 
or the flexibility of a piano string, we 
change its pitch of vibration. In a 
piano, the mass of each piano string is 
fixed when the instrument is made, but 
the tension of each one can be varied at 



any time. If you look inside a piano 
you will see that the heaviest strings are 
tuned to the lowest notes and the tight- 
est strings (of any certain size) the highest 
frequencies. 

So it is in radio; among circuits of the 
same capacitance, those that have the 
most inductance will respond to the low- 
est frequencies. If the inductance re- 
mains constant, the circuits that have the 
least capacitance will be tuned to the 
highest frequencies. Piano tuning is 
nothing but tightening and loosening 
the strings until their pitches of frequen- 
cies are correctly spaced along the 
musical scale. Radio tuning is nothing 
but adjusting the condensers or induc- 
tors of a circuit until its best electrical 
vibration frequency is correctly in agree- 
ment with the frequency of the particu- 
lar wave (in the scale of radio frequencies) 
that it is desired to receive. 

"Now you are perhaps thinking that 
piano tuning is very different from radio 
tuning, after all, because a piano string 
is tuned to send out a note of a certain 
frequency, whereas a radio receiver is 
tuned to select an arriving wave of a 
certain frequency. In my next talk I 
will tell you how those two apparently 
opposite properties really go hand in 
hand. Until then, just bear in mind 
that when you want to hear WEAF 
without interference you must let your 
receiver build up currents of 610 kilo- 
cycles frequency and at the same time 
oppose the building up of currents of all 
other frequencies." 

On December 14, Mr. Hogan said 
from WEAF: "The coils and condensers 
in a radio receiver are used to get the 
effects of electrical tuning, so that the 
signals arriving at some desired wave 
frequency can be selected from interfer- 
ing signals carried by waves of other 
frequencies. By properly adjusting a 
variable condenser or a variable inductor 
(which is the engineering name for a coil) 
you can cause its circuit to become an 
easy path for currents produced by the 
WEAF waves of 610 kilocycles frequency, 
for example, and at the same time a hard 
road for currents of other frequencies; 
to traverse. A different setting of the 
condenser or inductor dial or switch 
will permit currents of WOR's fre- 
quency, 740 kilocycles, to flow easily; 
and similarly other adjustments corre- 
spond to the wave frequencies of other 
stations. 

"The variation of condensers and in- 
ductors in a radio set corresponds fairly 
well to changing the tension and weight 
of a piano string. Such an adjustment 
by changing the tuning, changes what is 
called the "natural frequency" of the 
radio tuner or the musical string. This 
natural frequency is the rate of vibrations 
which is the easiest for the tuned system.. 
If we tune a piano string to the frequency 
of 256 cycles per second, which is the 
pitch of middle C, it will give off a note 
of that frequency whenever it is dis- 
turbed or struck. That happens because- 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



27 



tuning the string to 256 cycles is nothing 
more than making its natural frequency 
256 cycles, so that its easiest or natural 
rate of vibration is 256 cycles per second. 
"The most interesting thing about this 
adjusting of natural frequencies is that it 
works both ways. Not only does a musi- 
cal string give off a note of its natural 
frequency when it is strongly struck or 
plucked, but it will pick up and start 
vibrating in resonance with a separately- 
produced sound of its natural frequency. 
If you tune two strings of a guitar to the 
same note, that is, so that they have the 
same natural frequency, you can make a 
simple experiment to demonstrate this. 
Pluck one of the two strings and immed- 
iately stop it from vibrating by putting 
your finger on it; you will then find that 
the second string has picked up the vi- 
brations of the first and is carrying them 
on, as you can readily prove by touching 
the second string with your finger and 
noting that the sound stops. If you try 
this experiment with the second string 
a little out of tune from the first, that 
is what a somewhat different natural 
frequency, you will find that the second 
string does not pick up the vibrations of 
the first. Of course, that is because the 
natural frequency of the second or 
"receiving" string is then not the same as 
the sound frequency of the first or 
"sending" string. 

"You may wonder what this has to do 
with radio. It is not hard to see how the 
first string may be compared to a radio 
sending station, and how the sound 
waves which the string gives off are in one 
sense like the radio waves sent out by 
the radio transmitter. In this same 
sense, then, the second guitar string is 
like a tuned radio receiver. This analogy 
may be clearer to you if we trace it step 
by step, so let us consider the sound 
waves first. 

"When the first guitar string is plucked, 
it vibrates at its natural frequency and 
produces sound waves of that same fre- 
quency. The sound vibrations travel to 
the second string; if this second string 
is tuned to the original frequency the 
arriving waves will set it into resonant 
vibration at their own frequency. If the 
natural frequency of the second string 
is not the same as that of the arriving 
waves, it will respond relatively feebly 
or not at all. 

"Now for the analogous radio case: 
When the radio transmitter is operated, 
it oscillates at its characteristic fre- 
quency and produces radio waves of that 
same frequency. The radio waves travel 
to the radio receiver; if the receiver is 
tuned to the original frequency the arriv- 
ing waves will set it into resonant vibra- 
tion at their own frequency. If the 
natural or tuned frequency of the receiver 
is not the same as that of the arriving 
waves, it will respond relatively feebly 
or not at all. 

"Thus we have a simple acoustic or 
musical example of what tuning is and 
how it can be used to select wave-vibra- 
tions of any desired frequency. The prin- 
ciples are the same as those that underlie 
radio tuning, the only differences being 
in the details. Sound waves are mechani- 
cal and usually occur in air; they are of 



audible frequencies, or say between 
sixteen cycles and 16,000 cycles a second. 
Radio waves are electrical and travel 
through space, not requiring even air to 
carry them. Their frequencies are ordi- 
narily so high that they cannot be heard 
directly, or say from ten or fifteen kilo- 
cycles on up to thousands of kilocycles. 

"The question that naturally comes up 
now is why, if the musical string will 
respond resonantly only to a wave of its 
own frequency, a radio receiver will 
respond to waves of frequencies different 
from the one to which it is tuned. We all 
know that the unfortunate fact is that 
many radio receivers do bring in inter- 
ference; a good many of you who are 
listening to me now are at the same time 
hearing interfering signals that are 
carried to you on waves having frequen- 
cies quite different from WEAF's value of 
610 kilocycles. Yet is is fair to assume 
that all your receivers are tuned to 610 
kilocycles. 

"The answer to that question lies in 
what I called the "pitch sense" or selec- 
tivity of the receiver. Some receivers are 
capable of selecting a relatively narrow 
group of wave frequencies centering 
about a single definite value; others let 
in many wave frequencies in addition to 
the one which is desired. For instance, 
a good receiver tuned to 610 kilocycles 
will admit practically nothing from 
waves of 600 kilocycles or 620 kilocycles 
(which are respectively ten kilocycles 
below and above the central or resonant 
value of 610 kilocycles). On the other 
hand, a poorly selective receiver that is 
tuned to 610 kilocycles may also admit 
current from waves as much as 100 
kilocycles below and above the resonant 
value or from 510 to 710 kilocycles. As 
you can easily see, such a receiver when 
tuned to WEAF might also pick up sig- 
nals from WJZ on 660 kilocycles although 
it would probably exclude interference 
from WOR on 740 kilocycles. 

"What causes such a great difference in 
receiver selectivity? That is a question 
that bothers very many radio listeners. 
The answer is that receivers in which 
there is a comparatively large waste or 
loss of electrical energy are poorly selec- 
tive. Receivers that have well designed 
circuits and component parts and which 
therefore waste relatively little energy, 
are highly selective. The most common 
causes of poor tuning, are (1) bad aerial 
or ground connections, (2) incorrectly 
connected crystals, (3) poor tuning 
coils and (4) badly designed or badly 
built variable condensers. All of these are 
easy to remedy, and some attention to 
them will usually improve the selective- 
ness of any poorly-operating tuner. 
Sometimes none of these items is defec- 
tive, however, and still the receiving set 
will not tune properly. In such cases 
there is usually something radically 
wrong with the circuit arrangement or 
the layout of the parts." 



ceive American radio messages than other 
European countries, Consul-General 
Letcher reports from Copenhagen. 

Some of the Danish radio amateurs 
have made it a practice to "listen in" 
for Americans at about 3 or 4 o'clock in 
the morning. Recently several of these 
amateurs reported "getting" different 
broadcasting stations in the United 
States. One station mentioned parti- 
cularly was "Schenectady" with the call 
signal, WGY. Orchestra music, soloists 
and speeches were plainly heard. 

Interest in radio continues to increase 
in Denmark, the general says, and it is 
estimated that there are now approxi- 
mately 10,000 radio amateurs in the 
country. 



WRC Listens In 

Out of thousands who listen in on 
WRC, few know that WRC, as well as 
all broadcasters near the coasts, also 
listens in constantly, not on its own 
"stuff," speaking informally, but for 
ships. As the law requires every hour of 
the day while the big Class B stations of 
the radio corporation in Washington is 
on the air, one operator is listening in on 
600 meters, the ship emergency wave, 
for SOS calls. When one comes in, 
broadcasting is shut down until the air 
is cleared, usually by some coastal naval 
station. 

One Friday during the midnight show, 
the operator on watch at WRC heard an 
SOS from a ship off the coast of New 
York, and immediately pulled the switch, 
cutting off the power in the midst of a 
number by a local orchestra. Later, 
when NAH and NAO, naval stations at 
New York and Charleston, reported "all 
OK," WRC went on with her show. 
This was the third SOS call heard while 
the station was broadcasting, and shows 
the necessity of keeping a watch on the 
600 meter wave. If broadcasting kept 
up during the transmission of distress 
calls, it is doubtful if the calls would get 
through or whether aid would be brought 
to the ship; the law requires, however, 
that coastal stations cease operation when 
an S O S call is heard. 



Denmark Hears Us 

Enthusiastic radio amateurs in Den- 
mark are always endeavoring to catch 
broadcasting from the United States, 
even though this country lies in a some- 
what more unfavorable position to re- 



Station WJY Reopens 

After a brief period of silence, during 
which time extensive research and ex- 
perimental work has been in progress, 
WJY, the twin station of WJZ at the 
Radio Corporation of America's dual 
broadcasting station Radio Broadcast 
Central located in the Aeolian Building, 
New York City, has resumed broad- 
casting during its former periods on 
Tuesdays, Thursdays, Fridays and Sun- 
days on 405 meter wave-length. 

The reopening of the 405 meter chan- 
nel re-establishes the unique dual broad- 
casting installation which is an exclusive 
feature of Broadcast Central, permitting 
two distinct programs to be broadcast 
on different wave-lengths from closely 
associated antennas. The programs 
from station WJY are of the same high 
standard which has characterized sta- 
tion WJZ, including symphonic, classical, 
and popular music, noteworthy speeches 
and dinners, and events of major interest 
to the public. 



28 



RADIO AGE — "THE MAGAZINE OF THE HOUR' 



Amateurs Exchange Messages With France 



HARTFORD, CONN.— Reliable two- 
way communication between ama- 
teur radio operators in North America 
and Europe has been carried on fre- 
quently since the first two-way contact 
was made by F. H. Schnell, traffic man- 
ager of the American Radio Relay League 
of this city and Monsieur Leon Deloy 
of Nice, France, the night before Thanks- 
giving eve. This proves that interna- 
tional citizen radio communication across 
the Atlantic is now practicable. One of 
the thousands of amateur transmitting 
stations in the United States, using a 
wave length of 100 meters, can pick out 
and communicate direct with one of the 
many hundreds in France and England — 
this while the ether is humming with 
the medley of thousands of CW trans- 
mitters and broadcast stations are hurling 
DX music across the continent on other 
waves. 

Two-way short wave radio conversa- 
tions have been carried on not only be- 
tween Deloy's F8AB and those operated 
by Schnell and John Reinartz of South 
Manchester, Conn. 1MO and 1XAM 
respectively, but also three other Eastern 
amateur stations, 1XAQ, operated by 
S. Kruse and Boyd Phelps of this city, 
2CQZ by Robert M. Morris and 2CFB 
by Floyd M. Weise, both of Elizabeth, 
N. J. Deloy reported last night by 
radio that he had heard 9ZT, operated 
by Donald C. Wallace of Minneapolis, 
Minn., but that he could not work the 
American station. He also stated that 
the signals of 1MO came in stronger 
than the high power commercial station 
WSO. 

In reply to the first amateur radio 
message across the Atlantic on 100 
meters, General Ferrie, director of tele- 
graphs for the French government sent 
the following radio to the A. R. R. L. 
Headquarters: "Many thanks and most 
hearty congratulations on the results 
obtained with 100 meter wave, which 
have permitted the establishment of a 
new bond between France and the 
United States." The message was sent 
by way of Monsieur Deloy's station 
and was received at amateur station 
1MO here. 

It is impossible to describe fittingly 
the great amount of detail, the careful 
recording of time schedule, the exact 
precision in the tuning of respective 
sets that made it possible for the French 
amateur to transmit on his key the 
brief "GM, OM," meaning "GooH 
Morning, Old Man" in answer to the 
clear call, "8AB fu 1MO," that came 
from America. It was early morning in 
France when that message was heard, 
though it was exactly 10:30, eastern 
standard time, in Connecticut. 

The receipt of that simple greeting 
from the darkness out over the ocean 
to the point where it was nearing day- 
light on the other continent carried with 
it a feeling that only an amateur could 
appreciate and only a ham, that was 
used to "boiled owl" practices that keep 
him at his key through long anxious 
hours, could adequately express for it 



meant realization of the dreams of all 
short wave radio fans. 

This brings us to the scene at amateur 
station 1MO, at Hartford, which marked 
the beginning of the transmission tests 
with Europe on that night after Mr. 
Schnell had obtained the sanction of 
the Radio Inspector of the first district 
to transmit on 100 meters. 

For two nights in succession Schnell 
had listened to the peculiar note of 8AB 
like a string of r's run together and just 
the suggestion of an h like r-h-r-r-r- 
r-h-r-r- in steady beat and on the previous 
night he had copied two complete mes- 
sages so that his fingers fairly ached to 
grasp the key and hurl lMO's shrill note 
in the air. He sat down in front of the 
transmitter and ran his fingers nimbly 
over the set tuning it down to the proper 
100 meter wave length. 

This at 9:25 and he listened for fully 
fifteen minutes before he heard the 
French amateur's note calling "A1MO 
(the prefix A being for America) de 
F8AB, GM, OM, here messages." Num- 
ber 3 read: 

"Your cable establishing midnight 
schedule received this morning. I con- 
sider it as cancelled by your agreement 
to my message No. 2, sig. F8AB." At 
9:38 this message was ended and Deloy 
sent: 

"No. 4 A1MO, Tomorrow will not 
be on at this time, pse listen at 0500 and 
transmit at 0515 sig. F8AB." The 
figures given represent the transmitting 
time schedule in Greenwich Mean Time. 
Not knowing of course whether these 
messages had been received in the United 
States, Deloy went on and repeated 
both of them over a second time, after 
which he stood by for about ten minutes 
and repeated them a third time. At 
exactly 10:27 he signed off calling A1MO, 
A2BY, CQ de F8AB. 

At the moment that the lid went off 
the amateur quiet period for the benefit 
of broadcasting at 10:30, Schnell threw 
over his antenna switch and grasped 
the key to test the result of many months 
of planning. Thousands of amateurs 
could understand his emotion. 

"8AB fu 1MO" clicked out into the 
air and traveled across to France where 
it struck and vibrated at Deloy's re- 
ceiving antenna at Nice. 

"RRR," he went on "messages re- 
ceived signals QSA." He called and 
repeated until 10:37 and a moment later 
the silence broke with: 

"A1MO de F8AB rr QRK Your sig- 
nals QSA vy one foot from phones on 
Grebe. FB OM Hearty Congratulations. 
Two-way communication between the 
continents had been established but to 
the great surprise of both operators it 
was not for a brief second or two, giving 
them credit for the accomplishment 
and nothing more but steady and re- 
liable communication that was continued 
for two hours. 

"This is a fine day" called Deloy joy- 
ously, it appeared. "Pse QSL No. 1 
and No. 2." 

"O. K. FB QSA QTC QRV? (Meaning 



signals loud) I have messages. Are you 
ready to receive them?" 

This was 10:50 and the French ama- 
teur came back. "Sure, go ahead with 
messages, words twice." As he was 
signing off, Schnell heard him call 
AlXAM, the station operated by John 
Reinartz at South Manchester, Conn., 
only a few miles awav saying: "Pse 
QRX until after A1MO." 



Substituting Tube for Crystal 

(Continued from page 25.) 
the socket being placed 2 inches behind 
the panel. 

A .001 mfd fixed mica condenser is 
essential across the phones to by-pass 
radio frequency as otherwise circuit 
will not, usually, oscillate. 
Wiring 

All connections are to be made with 
either No. 16 or No. 18 tinned copper 
wire which should not touch panel or 
base except at points where connection 





to binding posts make it necessary. If 
attention be given to these details the 
set will be so stable that its controls can 
be touched without acting as the least 
deterrent to long range reception. 
Tuning 

While we have four controls, it is 
necessary to tune with two, only. To 
tune: turn all controls to zero. Turn 
detector tube on until, with a U V 200 
tube, a hiss like that of escaping steam 
is heard (a vernier rheostat is not neces- 
sary to make adjustment). Now turn 
down rheostat until the hiss ceases and 
set is quiet. Turn switch to the third 
contact (with a one hundred foot 
antenna), or to the fourth or fifth contact 
for a shorter system. 

Note that by turning tickler coil to 
maximum a click will be heard in the 
phones and if completely turned to 
maximum a howl will be encountered. 
Return to zero and increase wave length 
by turning in condenser plates until a 
station is received. Volume is then 
increased by rotating tickler. After 
having received a station and determined 
its wave length observation of condenser 
dial position will show the wave length 
to which you are tuned. 

For long range reception the condenser 
and tickler are worked together because 
the point of most sensitive and loud 
reception is that at which the click in 
phones is heard and the position changes 
with the wave length. Never turn the 
tickler further than to this critical 
point. To do so merely distorts signal, 
decreases audibility, and makes havoc 
with your neighbors reception. 



RADIO AGE— "THE MAGAZINE OP THE HOUR' 



29 



roadcasters 




(News for this department is solicited from all stations) 




SPEAKING TO 25,000,000 
President Coolidge delivering his first message to congress in the presence of a throng, of national notables. 
For the first time in the history ^of the United States millions of Americans from coast to coast heard a President 
delivering his message. His voice was clearly broadcast by radio from local stations and relayed across the continent. 
Several of the microphones that picked up the President's voice for transmission by telephone to various broadcast- 
ing stations are seen in the photo. (Kadel & Herbert.) 



WHEN President Coolidge ad- 
dressed Congress en December 6 
his words were heard all over the 
United States in cities and hamlets and 
on farms, on the borders of the wilder- 
ness and in isolated mountain homes. 
Radio did this. It made history that 
day, for it established the efficacy of 
this means of enabling a President to 
address the whole people. 

The message was broadcast by WCAP 
at Washington and was relayed by 
various other stations to the far corners 
of the United States. 

An interesting comment on this 
achievement was written by Oswald 



Schuette, editorial writer on the staff 
of the Chicago Herald and Examiner, 
which, by the way, is the Chicago morn- 
ing newspaper that has given its support 
whole-heartedly and enthusiastically to 
promotion of radio. We republish the 
editorial: 

r 1 ^WICE in five days the voice of the 
J- President of the United States has 
been broadcast across the continent by 
the marvel of the radio. 

It is estimated that 25,000,000 people 
heard each of the addresses. The first 
was his first message to Congress, deliv- 
ered last Thursday. The second was 



his memorial speech for the late Presi- 
dent Harding on Monday. 

Even in these days, when science finds 
it difficult to surprise a world accustomed 
to surprises, there is something miracu- 
lous in the thought that the frail human 
voice of the President at Washington 
should be carried through the air to the 
corners of this vast continent. 

But there is a far more important 
aspect to this achievement. That is its 
effect on the unity of our national life. 

When the United States was estab- 
lished among the nations of the world, 
the greatest peril which its founders 
feared was the clash of opposing inter- 



30 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



ests. New York and Virginia, though 
but a few hundred miles apart, were so 
widely separated in the social and 
economic lives of their inhabitants that 
there was every reason to fear the new 
Union would be endangered by this 
divergence. When President Washing- 
ton delivered his first message to the 
first Congress at New York in 1789, it 
took weeks, and even months, before the 
printed copies of that address could reach 
the remote hamlets of Virginia, to say 
nothing of the farflung boundaries of 
Massachusetts and Georgia. 

What would the fathers of the nation 
have said if they could have looked into 
the future to the day when the Consti- 
tution they framed would have to stand 
the strain of the diverging interests of 
Maine and California, of Florida and 
Alaska? And what would they have 
said if, looking into that future, they 
could have seen the President at Wash- 
ington speaking, not to an assembled 
handful of congressmen, but speaking, 
with his own voice, to 25,000,000 of his 
countrymen? 

From Washington's inaugural to Presi- 
dent Coolidge's first address to Congress, 
134 years have passed into the crowded 
history of the United States. From 
thirteen struggling colonies on the nar- 
row coast of the Atlantic, the nation has 
grown across mountains and rivers and 
oceans until it is today the greatest 
republic in the world. But it is more 
united today, in all its vast expanse, 
than it was in its confined limits nearly 
seven score years ago. It owes that 
union to many contributing causes. 

And the latest of these is the Wonder 
of the Radio. 



33 Broadcasters Quit 

WASHINGTON, D. C— Less than 
500 broadcasting stations will 
be in operation with the advent 
of 1924, officials of the Department of 
Commerce predict. These stations will 
be the best and most popular in the 
country, and will be more than enough 
to serve their communities; in some in- 
stances there will still be several in a 
single city. 

The deletion of broadcasting stations 
during the past six months has been quite 
rapid; the total reaching 149, whereas 
only 107 opened, showing a loss of forty- 
two stations. During the past month 
thirty-three stations fell by the way- 
side, so to speak, and only fifteen new 
ones entered the field. 

Apparently, as in many lines of en- 
deavor, it is to be a survival of the fittest 
race. On December 1, there were 549 
broadcasting stations still serving the 
public; forty-seven were the more power- 
ful Class B stations; 281 were in class A; 
219 in class C, and two were listed as 
Class D, or development stations. Of- 
ficials hope that the 219 class C stations, 
all of which are operating on the single 
wave length of 360 meters, will qualify as 
class B stations, transfer to class A or quit, 
thus eliminating considerable existing 
interference chiefly among themselves. 
The result would be a group of about 100 
big stations with distinctive wave lengths, 
and approximately 350 smaller stations 
with exclusive district waves. 




A RADIO CLOSE-UP 
Large crowds heard every word of the President's address to congress 
with the aid of radio amplifiers installed outside of the capitol. (Kadel & 
Herbert Foto.) 



The broadcasting service in this coun- 
try, which is of course privately owned 
and operated, and also leads the world 
in number of stations, is still holding 
public interest, the Department of Com- 
merce believes. Moreover, its perma- 
nency is assured. Its real value, how- 
ever, has not yet been fully realized, and 
will not be until there has been a wider 
distribution of receiving sets suitable for" 
the reception of varied programs from 
several stations, permitting the listener 
to select at will the class of service of 
greatest interest and value. 

The recent changes in wave lengths 
grouped weaker stations between 220 
and 280 meters and gave the more power- 
ful stations the wave lengths between 
280 and 546 meters. In this class, the 
longer waves usually are assigned to the 
more popular stations. It is only nat- 
ural that the more powerful stations are 
the most popular since listeners-in nat- 
urally tune in on accustomed channels 
where they get the big stations with no 
interference. These stations all broad- 
cast good programs and have a trans- 
mitting power which cannot be approach- 
ed by Class A or C stations. When fans 
try for smaller stations on the lower 
wave lengths, unless they have very 
selective receivers, they immediately get 
interference from the larger stations and 
the volume is appreciably less. 

The weaker stations are out of luck, 
so to speak, in another line; they find 
that the larger stations come into their 
territory if not their actual stations and 
get the best talent together with their 
following. The cost of maintenance is 
tremendous, besides the initial cost aver- 
aging about $125,000 and few small 
operating companies can keep up the 
pace. The big electric-manufacturing 
companies are exempt, of course, as well 
as some other interests which got off 
with an early start, expecting no return. 



These include some big department 
stores, large municipal daily papers, 
some national organizations and manu- 
facturing companies, such as comprise 
the present forty-seven Class B stations. 
For the small concerns, the maintenance 
for good operation is a steady drain on the 
exchequer which they cannot meet and 
the advertising is not of sufficient value. 

Students of the situation today de- 
clare there is no need for smaller broad- 
casters in cities where there are one or 
two large stations in constant service. 
The craze to broadcast, which was at 
first a popular fad, is now established on 
a positive operating basis, serving a prac- 
tical need in almost every big community. 

While some minor stations may con- 
tinue in smaller districts where farmers 
are served, others, such as more prosper- 
ous papers, may function despite the 
cost, just for the intangible goodwill, 
and some churches and hotels may op- 
erate to extend their scope and adver- 
tising. Many believe our broadcasters 
will eventually be reduced to one-half 
the total today. 



Broadcast Program Analysis 

A RECENT vote of broadcast listen- 
- r ^- ers taken by three Chicago stations 
has aided tremendously in arriving at a 
definite idea of what kind of programs 
the fans prefer. One of the most inter- 
esting disclosures of the vote was the 
vast size of the listening audience. An- 
other was the fact that only 1.7% of the 
listeners want grand opera. In view of 
the almost desperate efforts one station 
has made recently to take over unto it- 
self the control of opera broadcasts, the 
latter figure is rather humorous. Two- 
thirds of the 263,000 who mailed in their 
votes were men. Almost one-fourth of 
them wanted classical music and only 
.2% wanted to hear male quartets. 
Believing that an analysis of the vote 



RADIO AGE— "THE MAGAZINE OP THE HOUR' 



31 



would be equally interesting to broad- 
casters and broadcast listeners Radio 
Age requested such an analysis from E. 
F. McDonald, Jr., and he has supplied 
the following information: 

"For a period of twelve days, three 
Chicago broadcasting stations made the 
same announcement. These three sta- 
tions were the Westinghouse Electric 
and Manufacturing Company, station 
KYW, the Chicago Board of Trade, sta- 
tion WDAP, and the Zenith-Edgewater 
Beach Hotel Broadcasting station, 
WJAZ. Each of these stations asked 
its listening audience what it desired to 
hear most. We asked them whether they 
preferred to hear classical, popular, jazz, 
instrumental, vocal, religious, political, 
educational talks or what. We told them 
that their desire would have a great in- 
fluence on the future of radio broadcast- 
ing. We also announced that each listen- 
er could have only one vote and that if 
more than one vote were sent in, or if the 
same person sent votes to two of the sta- 
tions, neither one of them would be 
counted. We have found no duplication. 

"The three stations received in these 
twelve days a total of 263,410 pieces of 
mail. KYW brought in 37,900 of these, 
WDAP 54,811 and WJAZ 170,699. Con- 
servative advertising men estimate that 
not more than one in fifty of our listeners 
will respond regardless of what the in- 
ducement offered is. This indicates a 
listening audience of 13,170,500. Tak- 
ing the figures of the Zenith-Edgewater 
Beach Hotel Station of 170,699, this 
represents a listening audience on this 
one station alone of 8,534,950. Station 
WJAZ in one day received 20,152 pieces 
of mail, representing an audience of over 
a million for a single night. 

"I am enclosing herewith a list of the 
responses received by WJAZ divided into 
states up to the time we had received a 
total of 122,000. After this time the re- 
sponses were coming so rapidly that we 



could not sort them into states rapidly 
enough. An analysis of the desires of 
the listening audience shows us that: 

2.7% desire band music. 

24.7% desire classical music. 

2.9% desire dance music. 

.3% desire dramatic music. 

1.0% desire Hawaiian music. 

18.4% desire jazz. 

.3% desire Mexican music. 

.3 %• desire male solos. 

5.7% desire old-time songs. 

1.7% desire grand Opera. 

.9% desire orchestra. 

.5% desire pipe organ. 

29.0% desire popular music. 

.3% desire quartet instrumental. 

.2% desire male quartette. 

.8% desire mixed quartettes. 

.5% desire religious music. 

2.1% desire sacred music. 

.7% desire saxaphone. 

.6% desire symphony music. 

2.1% desire vocal selections. 

"Of the responses received 32.5% were 
from women and 67.4% were from men." 

Following is a table of the votes by 
states: 

United States 

Alabama 425 

Alaska 3 

Arizona 38 

Arkansas 1004 

California . 315 

Colorado 1 172 

Connecticut 635 

Delaware 90 

District of Columbia 134 

Florida 59 

Georgia 399 

Hawaii 1 

Idaho 24 

Illinois 40880 

Indiana 3482 

Iowa 6435 

Kansas 3899 

Kentucky 798 

Louisiana 358 



Maine 123 

Maryland. 457 

Massachusetts 1323 

Michigan 3707 

Minnesota 4421 

Mississippi 416 

Missouri. 3677 

Montana 524 

Nebraska 3146 

Nevada 12 

New Hampshire 148 

New Jersey 983 

New Mexico 128 

New York 6245 

North Carolina 271 

North Dakota 3429 

Ohio 6861 

Oklahoma 1992 

Oregon 62 

Pennsylvania 5964 

Rhode Island.... 98 

South Carolina 193 

South Dakota 1642 

Tennessee 1138 

Texas..... 2971 

Utah 6 

Vermont... 220 

Virginia.... 403 

Canada 4076 

Miscellaneous 2021 

Mexico 12 

Cuba..... 3 

Central America 1 

Bermuda 1 




HIRAM LISTENS TO CALVIN 
Senator Hiram Johnson is pictured at his New York campaign headquarters as he listened over the radio to 
President Coolidge's first message to congress, which was broadcast over the country on December 6. Senator John- 
son went to the east to consult with Frank H. Hitchcock, national manager, concerning his campaign for the re- 
publication nomination for president. (Kadel & Herbert.) 



32 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



What is Radio's Future? 



An era of simplification of radio broad- 
casting, with larger and more powerful 
distributing stations but with few new 
additions to the "science of radio," was 
forecast by Bowden Washington, builder 
of the world's most powerful marine sta- 
tions and United States naval equipment, 
in an address broadcast over the North 
American continent from the National 
Radio Show at Chicago. 

Mr. Washington's speech, delivered 
from the Cutting & Washington booth, 
was picked up and relayed by WDAP, 
Chicago; WLAG, Minneapolis; WJAZ, 
Chicago; a Cleveland station and Cana- 
dian stations. 

"I rather think we will have fewer 
broadcasting stations of higher power, 
better programs and more powerful re- 
ceivers," said Mr. Washington. 

"The small, independently operate'd 
station is doomed. They cannot get 
programs of the quality obtainable by 
the large stations, and since the novelty 
of radio has worn off, people are no long- 
er interested in listening to scratchy 
phonograph records. The dry cell tube 
has done a great deal to make the multi- 
tube set available to a great many more 



BOWDEN,Washington, radio 
engineer and designer, is 
the designer of seven large 
commercial radio stations in 
the United States, including 
WSA . (East Hampton, L. I.), 
the most powerful spark marine 
radio station in the world, 
with a maximum radius of 
11,000 miles. He was a de- 
signer of U. S. Naval equipment 
during the war, and also of 
ALLIED army and navy equip- 
ment. 

The speech printed herewith 
predicts the future of radio. 
We believe it may be of interest 
from that and other stand- 
points. 



will put up with a mess of wires, cords 
and batteries, but I feel that the radio 
receiver will soon be as necessary as the 
phonograph in the home, and this mess 
will not be tolerated. The demand will 
range from the simple cabinet model to 
the beautiful period console, an orna- 
ment to any living room. 



progresses slowly and logically, with a 
gradual improvement. 

"I have been following radio for twen- 
ty years. In 1913 I had a station-spark 
coil transmitter and coherer receiver — 
things most of you have probably never 
heard of. I have been following the art 
ever since, as amateur student and pro- 
fessional. I have yet to see anything ab- 
solutely revolutionary occur. 

"The vacuum tube is probably the 
greatest invention of the last half century. 
Until I became interested in home radio 
a few months ago, I was chief engineer 
of a company operating the radio of 900 
merchant ships. A large number of these 
ships are still doing good work with 
crystal detectors, and the vacuum tube 
was disclosed in 1907. 

"We read in every column of new 
circuits — in the newspapers and in every 
radio magazine- — the so-and-so circuit — 
the something-or-other. To my knowl- 
edge, there have been since 1910 but two 
radically new and useful circuits — the 
Armstrong regenerative and the Arm- 
strong super-heterodyne. Most of these 
alleged new circuits are the products of 
so-called radio experts. 




A general view of the first great rad 
shown. (Kadel & Herbert Foto.) 

people than ever before; not only by 
saving the price of storage batteries, 
charger, etc., but by making tube sets 
available to those in isolated districts 
where no means of charging storage bat- 
teries is at hand. I also believe that 
loud speaker operation will be demanded 
from all but the very cheapest sets, as 
will the self-contained feature. 

"People, for the thrill of a new thing, 



RADIO SHOW IN PARIS 
io show held in Paris. Many exhibits from America and other countries were 



"People who are putting off buying a 
set, or a better set, because they are wait- 
ing for some new and startling develop- 
ment which is coming out next month, 
or possibly even next week, are in error. 
Do you realize that there is no violent 
or radical difference between the radio 
telephone receiver of 1913 and the 
broadcast receiver of 1923? 

"Radio, like any other engineering art, 



"The present regenerative three-tube 
set is practically identical with a navy 
radio compass receiver of 1917 — there- 
fore, do not wait for the revolution. 
Enjoy radio now. 

"Another thing that I would like to 
mention, is the single circuit versus the 
double circuit receiver. This seems a 
bitter controversy, yet each has its uses. 
The single is easy to tune, having two 
major controls instead of three. 



RADIO AGE— "THE MAGAZINE OP THE HOUR" 



S3 




Radio fans listening to demonstration of "B" battery practice at the Philadelphia Radio Show. Near the dem- 
onstration board the fans may be seen grabbing for copies of the booklet, "How to Get the Most Out of Your 'B' 
Battery," of which they took 20,000 during the five days of the show. 

With the Manufacturers 



Phonographs and Radio 

In an interview, Mr. H. L. Willson, 
president of the Columbia Graphophone 
Company, explained the position of the 
phonograph industry in relation to radio 
broadcasting. 

"A happy relation is rapidly being 
established between the radio broad- 
casting interests and the phonograph 
industry. In some quarters, when radio 
first sprang into prominence, there was 
a feeling that the phonograph industry 
would be unfavorably affected, but the 
experience of more than two years has 
proven that radio may become a great 
aid to the phonograph industry. In the 
end, anything that helps to increase 
the popularity of music helps the sale 
of phonograph records. Radio serves 
to popularize music but as soon as a 
number is rendered at a radio broad- 
casting studio, no record of it remains. 
The radio audience is not satisfied with 
one reproduction. This is indicated by 
the many request programs which are 
arranged in an attempt to meet the de- 
mand for a permanent record of success- 
ful numbers. Famous orchestras some- 
times receive as many as 500 telephone 
requests for certain numbers. Only a 
phonograph record personally selected 
can suit the indivudual tastes of this 
diversified audience. 

"Realizing that radio broadcasting 
is an effective way of bringing new mus- 
ical numbers to the attention of the 
public, just as the phonograph is the 
only successful way to permanently 
record them, the Columbia Graphophone 
Company has made arrangements with 
the American Telephone and Telegraph 
Company to broadcast through WEAF 
selections by the same artists who are 
recorded on phonograph records at our 
studios. The selections by radio will 



be played exactly as they are reproduced 
on Columbia New Process Records. 
As a result of these arrangements, the 
radio audience gains excellent program 
matter while the phonograph industry 
profits in creating a demand for per- 
manent reproductions of the radio 
programs." 

A New "B" Battery 

A new type of "B" battery constructed 
on the skyscraper principle, so that most 
of its bulk is raised vertically instead 
of occupying valuable horizontal space, 
is now available to radio fans whose 
table area is limited. The new battery 
is No. 764 of the National Carbon Com- 
pany. It gives 22 1-2 volts, and is only 
3 1-8 inches wide. Its height is 5 5-8 
inches. 

It has been the practice of many radio 
users to install in their home sets the small 
"B" battery designed for portable sets, 
in situations where the saving of space 
or in the first cost were considerations. 
Some set manufacturers, to provide 
cabinet space, have done the same thing. 
Although the small "B" battery is 
necessary for portable use, its small 
size gives so short a life that it is properly 
used only where small space and light 
weight are of first importance. 

The new battery has twice the life 
of the portable battery, while standing 
on practically the same size base, and 
the cost is only about one-fourth more 
than the cost of the small one. It was 
developed after months of experimenta- 
tion by engineers of the National Carbon 
Company, who knew that many radio 
users were increasing their battery 
operating cost in order to economize on 
space or to save in first cost. The new 
battery gives much lower operating cost 
without appreciable sacrifice in table 
space. 



Cascade Regeneration 

A radio receiver set which, with a 
dishpan for an antenna, catches broad- 
casts from a 500 Watt Station 1,400 
miles away, has been developed by 
Bowden Washington, it is announced 
by the Cutting & Washington Radio 
Corporation, Minneapolis. 

The receiver, the result of two and a 
half years of laboratory efforts, works 
on a somewhat new principle termed 
cascade regeneration, which renders ex- 
tremely small antennae highly effective. 

With four UV-199's and a dishpan 
on a chair for an antenna, and another 
on the floor directly beneath it for a 
"counterpoise," signals from a 500-watt 
Western Electric transmitter in Dallas, 
Texas, were heard 1,400 miles distant 
on a loud speaker with such intensity 
as to be unpleasant. The receiver works 
equally well with a fly screen, a 6-foot 
wire, a magnavox horn or any small 
body of metal for an antenna, the an- 
nouncement said. The receiver is also 
extremely selective. 



Vernier Control 

Radio Units, Inc., Webester Bldg., 
Chicago, has attractive folders describ- 
ing the "Tiny-Turn," a vernier control 
which has a high gear ratio and makes 
tuning easy. They also offer the Duo- 
Spiral, a loop aeri»l with long handle 
and dial to regulate direction. The same 
company makes a binding post of black 
and nickel finish which improves ap- 
pearance of the panel. 



Bradley Switch 

The Allen-Bradley Co., Milwaukee, 
Wisconsin, have added a fourth item to 
their list of radio products, known as 
the Bradley switch. This is a very com- 



34 



RADIO AGE — "THE MAGAZINE OF THE HOUR" 



The How and Why of the Neutrodyne 



By ARTHUR B. McCULLAH 



THE ideal condition for amplify- 
ing at radio frequencies is to have 
the grid circuit tuned to the in- 
coming signal that is to be amplified; also 
to have the plate circuit tuned to the same 
value that the grid or secondary circuit 
is tuned to. That is, the greatest ef- 
ficiency is obtained when both grid and 
plate circuits are tuned to the same wave 
length. 

One of the properties of a vacuum tube 
is to oscillate when the grid and plate 
circuits are tuned to the same value, 
which is due to the capacity coupling, 
furnished by the elements of the tube. 
The tube can be made to stop oscillating 
by biasing the grid. This can be done 
with a potentiometer, but this method 
has not proved satisfactory. 

It can be readily seen that if a tube is 
oscillating at the frequency of the in- 
coming signal, the oscillations from the 
tube will "buck" the incoming signal, 
and produce nothing but howling and 
distorted music. 

The method to tune such an outfit, is 
to detune the plate circuit, so that the 
tube will not oscillate; that is, to detune 
the plate circuit, to a point just before 
the point where the tube will oscillate. 
With this method of tuning, the signal 
is relayed from the antenna to the de- 
tector, for a loss as the voltage across the 
tuning circuit in the plate circuit falls 
off very rapidly. By actual compari- 
son it has been found that the 
three circuit regenerative system gives 
by far louder signals than the radio fre- 
quency amplifier of this type. 

Prof. L. A. Hazeltine surmounted all 
of the difficulties by neutralizing the in- 
herent capacity of the tube that is so 
objectionable. The balancing or neu- 
tralization of the capacity feedback be- 
tween the grid and plate circuits is done 
with a small condenser in the neigh- 
borhood of .000015 mfd. 

In this system the grid and plate cir- 
cuits are tuned to the same wavelength, 
thus the maximum voltage will be across 
the tuned circuit in the plate circuit of 
the radio frequency amplifier. The tun- 
ing of such a set is not so critical as the 
tuning of a set that oscillates. 

The neutrodyne condenser probably 
gives more trouble than anything else 
in a neutrodyne set. A large share of the 
neutralizing condensers on the market 
are too small. This makes it impossible 
to neutralize the capacity feedback; 
also the full benefit can not be derived 
from such a set. 

A neutralizing condenser can be made 
that is the right size and will be just 
as efficient as the ready-made condenser. 
All that is necessary is two copper plates 
two inches square, soldered to the ends of 
two copper bus bar wires, one piece of 
bakelite 8 1-2 inches by 3 inches by 3-16 
inches, two long binding posts (see Fig- 
ure 1). 



roLOER. 




HOLE FOR 
SCREW 



<^ 6 &A/r£UT£ Q" X J 

Figure 1. The Neutrodyne Condenser. 



trodyne receiver, illustrated with a full page 
isometric draiuing, was published in the 
October RADIO AGE. Back copies are 
available at the regular rate of thirty cents 
for back numbers. 



With the Manufacturers 

(Continued from page 33.) 
pact, completely enclosed, single-pole 
switch for opening battery circuits. It 
is mounted by drilling a hole in the radio 
panel and securing the switch by means 
of a knurled nut. The switch is operated 
by pulling or pushing the switch button. 
The Bradley switch is nickel-plated 
and the button is polished black, thus 
conforming with the standard finish 
used for radio equipment. The switch 
will retail for sixty cents. 



Rogers Radiometer 

A device for tuning out interference 
is offered by the Rogers Radio Co., 
Pittsburgh. It is called the Rogers Re- 
ceiving Radiometer and sells for $3, 
list. Some of the merits of this radio- 
meter are that it is devoid of self-ca- 
pacity; its inductance is progressively 
variable; it occupies small space; it is 
of moulded condensite; easy to mount 
and is substantially constructed. Tested 
and approved by Radio Age Institute. 



Combined Battery and Charger 

The Philadelphia Storage Battery 
Company announces a big demand for 
the $20.20 Philco Charger-Battery com- 
bination. It is a charger for "A" and 
"B" batteries and a genuine "Philco" 
50-ampere radio battery, big enough to 
operate as many as five tubes. Further 
inquiry may be made of J. N. North, 
manager of the radio department, Phila- 
delphia Storage Battery Co., 1621 S. 
Michigan Ave., Chicago. 



Editor's Note; Comprehensive instruc- 
tions on how to build the four-tube neu- 



Battery Demonstrations 

A demonstration board which graphic- 
ally illustrated the factors affecting "B" 
Battery current drain attracted attention 
at the Philadelphia Radio Show, which 
closed November 17. The same board 
was moved to Chicago for the show there, 
and went on to Boston for the Boston 



Show, December 3 to 8. The board was 
part of the exhibit of the National Car- 
bon Company, and was manipulated by 
F. T. Bowditch, physicist, the associated 
company of the Union Carbide and Car- 
bon Research Laboratories, Inc. 

Just how much interest was shown in 
this battery demonstration may be im- 
agined from the fact that the radio fans 
took away with them 20,000 National 
Carbon Company booklets describing 
battery operation, during the time the 
show was on. And the fans literally 
took them as the photograph shows. 
Each demonstration closed with the an- 
nouncement that the new booklet, 
"How to Get the Most Out of Your 'B' 
Battery," might be had for the asking. 
Fans at once surged forward toward the 
booth, seizing the booklets the instant 
they came within arm's reach. One of 
these onslaughts is shown in the photo- 
graph, made during one evening at the 
show. The booklets rehearsed the in- 
formation given by Mr. Bowditch during 
his talk and demonstration. 

The demonstration board stood at one 
side of the booth and was constructed 
with a huge ammeter running across the 
top. As Mr. Bowditch explained the 
effects on battery life of the number of 
tubes, "B" battery voltage, use of a 
"C" battery, etc., the needle of the 
ammeter swung backward and forward 
across the dial, clearly visible to the 
farthest corner of the crowd. The 
demonstrator was able to talk in a nat- 
ural voice by means of a unit of the 
Western Electric public address system 
in front of the board. 

Besides the demonstration board, the 
National Carbon booth contained two 
large display stands which carried all the 
different types of Eveready radio bat- 
teries, with large lettered cards explain- 
ing the use of each in different radio 
installations. 

In addition to Mr. Bowditch, the Na- 
tional Carbon Company was repre- 
sented by G. C. Furness, manager of the 
radio department; A. M. Joralemon, 
sales manager, radio department; E. E. 
Horine, radio engineer; and E. Harold 
Boudwin, Philadelphia representative. 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



35 




THE Troubleshooter Department of 
RADIO AGE has become a pop- 
ular section of this magazine due 
to the fact that fans may write and re- 
ceive answers to their inquiries with a 
minimum of delay. 

In order that we may keep up the 
standard of this department and assure 
our fellow readers prompt service, it 
has become necessary for us to ask fans 
who write this department to observe 
certain rules, in order that prompt re- 
plies and concise answers may be sent out. 
Non-subscribers may avail themselves 
of this service if they enclose fifty cents 
with each letter of inquiry. Do not 
ask us to answer your inquiries if you do 
not remit, saying that you are a regular 
reader, as we cannot do this in justice 
to our regular subscribers. 

When writing, write on one side of the 
paper only, and do not forget to enclose 
a stamped, addressed envelope if you 
desire a personal reply. 

Before writing this department, search 
through your back numbers of RADIO 
AGE to see if the desired information is 
not printed therein. It will save you 
both time and money to do this, because 
if the information has already appeared 
in some past number, this department 
will only call your attention to the issue 
in which the desired information ap- 
peared. 

Questions pertaining to hookups of 
manufactured sets can not be answered. 
Write the manufacturer for this informa- 
tion. 

Do not ask the Troubleshooter depart- 
ment to send you a list of the best appa- 
ratus to use in a set. We can advise 
the type of apparatus in a general way, 
but cannot specify any particular piece 
of apparatus. If it is absolutely neces- 
sary to specify an instrument vitally 
necessary in the circuit without inten- 
tion of advertisement, it will be done. 

When writing, don't put down every 
question you can think of — stick to the 
particular subject you are asking about 
as much as possible. If it is a set, tell 
about how it functions, whether good, 
bad or indifferent. If you possibly can, 
enclose a diagram of the circuit you are 
asking about, as it becomes very per- 
plexing when a fan does not make clear 
what type of circuit he uses. 



Questions are answered in the order 
they are received, and if your letter is 
delayed, exercise a little patience. Many 
letters command special attention re- 
quiring reference to our files, and looking 
up information. 

This important service is carried out 
by our Technical Assistant, Felix Ander- 
son, under the supervision of Frank D. 
Pearne, Technical Editor of RADIO 
AGE. 

In an effort to start the year right, 
and settle for once and always the rub- 
ber stamp variety of question, we are 
printing this month questions of general 
and interesting nature. For the benefit 
of those who are just starting, we print 
the following general information: 
Antennas: 

Most preferred and popular type, is a 
single wire from 100 to 125 feet in length, 
including lead-in. For further informa- 
tion see June, 1923, issue. 
Grounds: 

Use waterpipe, or iron stake driven 
into ground. SOLDER the connection. 
Instruments: 

Use instruments that are strong, and 
well built. Do not expect results from 
cheap apparatus. Condensers should 
have positive connections and a gearing 
adjustment is preferred over any other 
type of vernier due to its lower losses. 
Choose a condenser which has the rotary 
plates connected to the end mounting, 
and has a minimum of insulation so 
placed with respect to electrostatic field 
that its losses are small. Friction 
verniers are also good. 
Selectivity of Sets: 

Depends upon the type of set, the lo- 
cation it is operated in, the proficiency of 
the operator, and the length of antenna. 
Tubes: 

Dry cell tubes will not give the volume 
that can be gotten from storage battery 
tubes. 



H. F. H., Jamestown, N. Y. 

Question: Kindly inform me where I 
can obtain a copy of the diagram of the 
Cockaday Four Circuit Tuner. I have 
read with considerable interest the com- 
ment of your readers on this circuit. 

Answer: Full instructions relative to 
the construction of the above circuit 
appeared in the August, 1923, issue of 
RADIO AGE. 



A. C. H., Chicago, 111. 

Question: Last week I built my first 
tube set from the isometric sketch show- 
ing back panel arrangement and wiring 
as given in the October issue of RADIO 
AGE. To say that it is a good hookup is 
putting it mildly. I wired my set as 
per your sketch and was able to get 
KDKA, WOS, WDAF, and WDAO the 
first silent night, and I have since brought 
in KDKA through local stations. It is 
my desire to build two steps of audio 
amplification with jacks so that I may use 
one or two steps and as I do not under- 
stand the circuit drawings, I am wonder- 
ing if you could supply me with an 
isometric sketch showing arrangement 
and connections of parts. With many 
thanks for the help you have already 
accorded me, I await your further in- 
formation. 

Answer: The August issue of RADIO 
AGE contained detailed information on 
the construction and operation of a two- 
stage audio frequency amplifier with 
jacks. Inasmuch as the article is illus- 
trated isometrically, you should have 
no trouble in connecting the set. 



E. W. R., Orlando, Fla. 

Question: Kindly inform me in what 
issue details concerning the construction 
of a battery charger were printed. I 
note in your questions and answers 
department you refer to a charger that 
can be operated from the 100 volt light- 
ing circuit. 

Answer: The information you desire 
was printed in the December, 1922, issue 
of RADIO AGE, and refers to an elec- 
trolytic type of battery charger. 



G. A. J., Joliet, 111. 

Question: I am a beginner in the 
radio game and in the course of my try- 
ing to get acquainted with the particu- 
lars concerning sets, I have acquired a 
number of radio parts of which I am 
enclosing a list. I would appreciate your 
giving me a circuit which would use these 
pieces of apparatus and which would 
really tune in long distance stations. 

Answer: In the October, 1923, issue 
of RADIO AGE you will find a circuit 
applicable to the apparatus you list and 
which will do consistent and long dis- 
tance work. The December, 1923, issue 



36 



RADIO AGE — "THE MAGAZINE OF THE HOUR' 



shows how to add two stages of audio 
frequency amplification to a set of this 
kind. 



G. W., Hailey, Idaho. 

Question: Please tell me how the 
various dry cell tubes compare as to 
volume and efficiency; also kindly send 
me a copy of the Kaufmann circuit. 

Answer: The dry cell tubes are all 
efficient as far as current consumption 
is concerned. I would list them as fol- 
lows, their efficiency rating in the order 
named: C 301A, UV 199, WD 11, 
WD 12, DV 6. Complete description 
giving detailed information on how to 
construct and operate the Kaufmann 
circuit was printed in the June, 1923, 
issue of RADIO AGE. A diagram of the 
two stages of amplification appeared in 
the September, 1923, issue. 



R. H., Belleville, Ohio. 

Question: Kindly inform me where I 
can obtain a copy of the three-circuit 
regenerative set, the type which uses 
two variometers and a variocoupler. I 
would like to have if possible the isometric 
sketch type showing the panel layout. 

Answer: A complete description of 
the Armstrong three-circuit regenerative 
set appeared in the November, 1923, 
issue of RADIO AGE. This issue shows 
the isometric sketch you desire. A 
diagram of the circuit in connection with 
a two stage audio frequency amplifier 
appeared in the September, 1923, issue. 



M. S. B., Minneapolis, Minn. 

Question: Early last spring I con- 
structed a radio set using the Kopprasch 
circuit. I am not able to recall in which 
issue it appeared. This circuit uses two 
variometers with an inductance between 
them. The set I made was dismantled 
by another person and I now want to re- 
build it, using the above circuit. Will 
you kindly oblige me with another copy 
of the issue in which it appeared? 

Answer: The circuit you have in 
mind appeared in the April, 1923, issue 
of RADIO AGE. A diagram of the 
circuit with a two-stage audio frequency 
amplifier was printed in the same issue. 



D. R. C., Logansport, Ind. 

Question: I am using a single circuit 
receiver with two stages of audio fre- 
quency amplification. Why is it that I 
cannot get as good results when I use 
more than ten volts on my detector and 
forty volts on my amplification? Please 
show me if there are any changes in my 
hookup that would better my results. 
Please tell me if there are any improve- 
ments I can make on my tuning arrange- 
ment. The coil consists of 90 turns of 
bank winding tapped at every ninth 
turn. This coil is wound on a three 
and one-half inch tube. The tickler coil 
has sixty turns of 26 DCC wire on a tube 
slightly smaller. 

Answer: Probably the tube you are 
using as a detector is defective. If it has 
too much residual gas remaining, the 
tube will not function well. Put it on 
the amplifier stage, and if it turns blue 
on 45 volts, you can be sure that it is too 



"soft." You might decrease the number 
of turns on the tickler, making the coil 
have about 50 turns. The set should 
oscillate freely with this number of turns. 
The other improvement I would suggest 
is to place your phone condenser across 
the terminals of the transformer on the 
first stage of amplification. I am en- 
closing herewith a diagram showing how 
this is done. This issue contains infor- 
mation relative to increasing the selec- 
tiveness of your receiver. 



L. E. D., Kansas City, Mo. 

Question: I am a subscriber and wish 
to get information regarding a Reinartz 
set I am going to build. In your Sep- 
tember issue, on page 5, you show how 
to load up a Reinartz set. As I look at 
the connections, it seems to me that when 
you switch in the loading coil you switch 
out the other coil and all the other switch 
points. The drawing does not show any 
connection between the two coils. Is it 
possible to wind a Reinartz coil large 
enough to take care of 600 meters? That 
is I want to reach this wave and higher 
without resorting to exterior loading coils. 
If this can be done, kindly advise me as 
to the specifications of such a coil. 

Answer : We rather prefer the arrange- 
ment shown in the September issue to a 
larger coil, as you will decrease the dead 
end loss of the additional turns used to 
bring the wave of the set up to six hun- 
dred meters. You might use larger con- 
densers. The arrangement shown in the 
September issue allows the outer coil to 
be used independently from the inner 
coil and when not in use, it is cut out 
of thecircuit entirely. Cutting out the 
coil in the above manner increases the 
efficiency of the set to a noticeable degree. 



W. K. R., Kennobert, Sask., Can. 

Question: Kindly inform me where 
I can obtain a description of an amplifier 
to be added to a single tube Reinartz 
receiver. 

Answer: This information can be had 
from either the August issue of RADIO 
AGE, or can be obtained from the Rein- 
artz booklet advertised elsewhere in this 



G. D. I., Tulsa, Okla. 

Question: Please give me a diagram 
of the circuit and a list of parts necessary 
to properly assemble the Haynes DX 
Receiver. 

Answer: Detailed information of the 
construction and operation of the receiver 
you have in mind appeared in the De- 
cember, 1923, issue of RADIO AGE. 
A diagram showing the addition of a 
two-stage amplifier was also shown in 
this issue. 



A. L. K., Watertown, N. Y. 

Question: Have been reading your 
July number of RADIO AGE, and I 
find it to be of mighty interest. I 
haven't been able to get this magazine 
on our news-stands, so please enter my 
subscription. I have an Armstrong 
three-circuit regenerative set at present, 
but I desire to get away from a regenera- 
tive type of receiver. Will I make a 



mistake in making a Reinartz set as in 
Figure 1 of your July issue? Would you 
please advise me something along this 
line? 

Answer: You apparently have the 
wrong conception of the Reinartz set 
when you infer that it is not regenerative. 
The Reinartz is one of the sets which 
makes use of this regenerative action, 
due to the plate coil being directly 
coupled to the antenna through the 
feedback condenser. If you intend to 
build a set of the non-regenerative type, 
we would suggest your constructing one 
as described in the September issue of 
RADIO AGE in which the tubes you 
mention could be used to advantage. 



B. W. E., West Burlington, Iowa. 

Question: Kindly inform me where 
I could obtain information relative to 
the adjustment of a Neutrodyne Re- 
ceiver. I am using one at present, and 
I am having trouble in making it work 
properly. 

Answer: Detailed instructions con- 
cerning the operation, construction and 
action of the Neutrodyne Receiver was 
published in the October issue of RADIO 
AGE. 



Experiments In Radio Control 

( Continued fr om page 24.) 
(Fig. 1) at A — B. Then, having set up 
the transmitter, say 20 feet or so away, 
press the key. You will find, perhaps 
after a little adjusting of the coherer, 
that the motor will operate simultaneous- 
ly with the transmitter. An electric bulb 
may be supplemented in place of the mo- 
tor, if desired. 

As an illustration of how explosives can 
be ignited at a distance by means of radio, 
here is a novel experiment: Connect a 
small piece of No. 36 bare German silver 
wire in the circuit at A— B. To this wire 
attach the fuse of an ordinary fire-cracker. 
Press the key of the transmitter, and the 
German silver wire will heat, and light 
the fuse, causing the fire-cracker to "go 
off." 

Another interesting experiment is the 
taking of flashlight photographs, without 
the presence of any person. Having set 
the camera as you would for a time ex- 
posure, connect the German silver wire 
in the circuit as in the preceding experi- 
ment, allowing it to touch the flash 
powder. Thus you can take photographs 
at a distance. 

Numerous other experiments which are 
needless to mention will suggest them- 
selves to the experimenter. 

Radio control will some day be com- 
mercially practical. Picture in your 
mind, huge, crewless, liners, laden with 
freight, sailing the seven seas, bound to a 
course at the will of the operator in the 
control station miles away, and this one 
possibility of radio control, will cause you 
to realize what it will mean to the prog- 
ress of our world. 



Don J t Fail To 
Renew Your 
Subscription 



RADIO AGE— "THE MAGAZINE OP THE HOUR' 



37 



PRICES REDUCED 

Send card today asking for our complete list 
of knocked down outfits and radio parts at 
reduced prices. Our book "Radio Construc- 
tion for the Amateur" will prove a big help 
to you. Price only fifty cents. A sample 
saving follows. You may order any part or 
parts you desire. 

Complete Regenerative Vacuum Tube 
Receiver. 

Approximate range 1,000 miles. 

Our Price Otherv 

Pane! 7"xl2" already drilled S 1.76 $ 2.60 

Cabinet k. d. of 3 ply wood to fit 1.60 2.60 

2 three inch diab at 30o each 60 1.00 

16 switch points with nut at .01c 16 .48 

4 switch stops with nut at .01o 04 .12 

8 binding posts, nickel plated at .03o .24 .48 
2 switch levers with \%" radius at .25o .60 .80 

1 filament rheostat. Good grade 60 1.00 

1 180° vario-coupler — 16 taps 2.76 3.50 

1 23 plate variable condenser 1.75 2.80 

1 tube socket of high Quality 45 .76 

1 phone and 1 grid condenser at . 15o .30 .50 

1 set transfers for marking panel 20 .30 

9 feet spaghetti tubing at -04o 36 .64 

1 tube socket support 20 .30 

20 feet Boft copper connecting wire 20 .30 

1 1 copy "Radio Construction for the 

Amateur" 50 .50 

$11.95 $18.32 
Some other articles from our list are: — 

Frost head set — 2000 ohms $ 3.45 $ 4.00 

Transformer — Audio frequency 

"Rhamstine" 3.00 4.00 

Detector tube — 6 volt — "Independent" 2.95 4.00 

Two step amplifier parts complete. . . . 13.95 21.50 
What They Say 
A great many unsolicited testimonials with 
reference to the above k. d. outfit have been 
received. A couple are: 

Roxbury, Connecticut. 
Am getting excellent service from one tuDe 
single circuit receiver which was bought 
knocked down from you. Have heard ninety- 
four stations including PWX at Havana, 
Cuba and my friends think it is great. 

John S. Robinson. 

Covington, Tennessee. 
The set which we made from your parts is 
giving good satisfaction. We have heard ] ,50Q 
miles or more air line. Have heard KLZ; 
KWH, KHJ, the last two being in Los Angeles, 
California. C. H. Owen. 

Radio Parts Manufacturing Company 

1Z47 Marlborough Depr. "C" Detroit, Michigan 



STA-RITE Auto Radio, 

BATTERIES SAVE YOU 60% 



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have been building batteries for over 8 years. 

TRY TO BEAT THESE PRICES 
AUTOMOBILE BATTERIES 
6 Volt, 11 Plate, Ford, Cher. Hup. Buick 

Cleveland, Durant $11.50 

« Volt, 13 Plate, Overland, Nash, Buick, Reo. Page 

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12 Volt, 7 Plate, Maxwell. Dodge. Franklin. $16.00 

OTHER SIZES ON REQUEST 

RADIO BATTERIES 



2 volt for W.D.I I &W.D. 1 2 
tubes run 300 hours on 1 
charge. $4.00 

4 volt forU.V. 199 $7.55 




6volt60amp.hr.$7.90 
6 " 80 - " 8.85 
6 " 100" " 10.60 
6 " 120" " 12.10 
6 " 150" " 14.80 
Allbatterias'are fully guaranteed in writ- 
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Send 10 per cent, with order, balance on 
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companies order. Shipped same day order 
received. Act now. 
STA-RITE BATTERY CO., Louisville, Ky t 




Be a RADIO EXPERT. Make big money. Win success 
in this new uncrowded field. Trained men needed. 
Learn quickly, at h ne in spare time, to con- 
struct, install, operate, repair, 
maintain and sell radio equipment^ 

RADIO EXPERTS EARN 

Short course, low cost, easy termi 

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I ffifJCp Wonderful tube receiving set of 

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; miles. Write today for "RADIO FACTS." 

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L_ 4513 Ravenawood Ave., Dopt. OOOO, Chicago 






Radio Year Book 

Radio, with other forms of communi- 
cation is included in a general survey of 
the economic situation of the world, 
just issued by the Department of Com- 
merce. This review which is known as 
"The Commerce Yearbook," and is 
available from the superintendent of 
documents, was prepared under the 
direction of D. J. Reagan, of the depart- 
ment. Concerning radio it states: 

"The principal developments in inter- 
national radio during the year 1922 were 
in the form of concessions secured, plans 
made and work prosecuted on various 
stations designed for international traffic. 
The station at Monte Grande near 
Buenos Aires, of which the Radio Corpo- 
ration of America is part owner, was 
taken over from the German company 
which had started its construction and 
the plans were altered to provide direct 
communications with the United States, 
as well as with Europe. The concession 
was secured for a similar high-power 
station in China, with smaller stations 
to act as feeders. This latter concession 
was issued in the name of the Federal 
Telegraph Company, which made ar- 
rangements to work with the Radio 
Corporation of America. The Radio 
Corporation secured the contract for 
the construction of a high-power station 
in Sweden, and proceeded with the con- 
struction of the station at Warsaw for 
the Polish government. These two 
stations furnish additional radio circuits 
direct to New York. 

"In Central America and on the 



Caribbean coast of South America, the 
Tropical Radio Telegraph Company 
developed a general plan for a radio 
network to cover the countries border- 
ing on the Gulf of Mexico and the 
Caribbean Sea. A new station was 
erected at Tegucigalpa, and the power 
of the New Orleans station was increased. 

"International radio communication 
during 1922 showed a large increase in 
receipts from transoceanic traffic, the 
Radio Corporation of America reporting 
gross receipts of $2,914,000 as compared 
with $2,138,000 in 1921. It is evident 
from these figures that radio has taken 
its place beside the ocean cable as a 
reliable means of international com- 
munication. They indicate also the 
possibility of operating high-power radio 
circuits at an actual profit — something 
that has never been accomplished before. 

"The most remarkable development 
in radio, however, was the great increase 
in the number of radio telephone broad- 
casting stations and in the number of 
receiving sets in use by the public. 
During the summer months of 1922 there 
was a slackening in the demand for radio 
apparatus and apparently a period of 
stagnation in the market. This proved 
to be only temporary, since, with the 
advent of the fall, the number of receiving 
sets in use increased even more rapidly 
than before and the requests for trans- 
mitting station licenses came into the 
Department of Commerce in even greater 
numbers. A remarkable increase appears 
in the gross sales of the radio corporation 
for 1922 — $11,286,000 as compared with 
$1,468,000 in 1921. 



Improve Your Radio 

Have you ever wanted a certain part for building a radio 
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38 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



What's What In Radio Industry 



r I "'HE Federal Trade Commission on 
-*- December 3 submitted to Congress a 
report of facts with respect to the radio 
industry. The report contains the re- 
sults of the investigation made pursuant 
to House Resolution 548, Sixty-seventh 
Congress, fourth session. 

An attempt has been made to collate 
the data with respect to the various 
phases of the inquiry as outlined by 
Congress in the resolution. In Chapter 
I, the facts concerning the development 
of the industry are presented which in- 
clude the organization of the Radio 
Corporation of America, the most im- 
portant factor in the industry. In Chap- 
ter II, the agreements between the vari- 
ous companies, respecting the hundreds 
of patents covering radio devices and ap- 
paratus, are discussed, which agreements 
are set out in full in the Appendix. In 
Chapter III are ' discussed the various 
traffic agreements respecting international 
radio communication and which are also 
set out in full in the Appendix. Chapter 
IV is devoted to a discussion of the prac- 
tices relative to the manufacture, sale, 
and use of radio apparatus and parts. 
This naturally includes an outline of the 
sales policy of the Radio Corporation 
and the facts as to its sale of vacuum 
tubes, which product has been termed 
the heart of radio. 

The Commission desires to call at- 
tention to certain facts disclosed by the 
investigation which may be summarized 
as follows: 

British Holdings 

The Marconi Wireless Telegraph Com- 
pany of America was the first company in 
America formed for the purpose of en- 
gaging in the transmission of messages by 
wireless. It was organized November 22, 
1899, with a capitalization of $10,000,000, 
of which about 25 per cent was owned by 
the Marconi's Wireless Telegraph Com- 
pany, Ltd., a British Corporation. 

In the United States and territories, 
this concern had the exclusive right to 
use and exploit the patents controlled 
by the British Marconi Company, among 
which were the important Fleming tube 
patents. The Marconi Company erected 
high power wireless stations at New 
Brunswick, N. J., Belmar, N. J., Marion, 
Mass., Chatham, Mass., Bolinas, Calif., 
Marshall, Calif., Kahuku, Hawaii and 
Kokohead, Hawaii. In the ship-to-shore 
communication business it practically 
had a monopoly when it was taken over 
by the Radio Corporation in 1919. Some 
of the wireless apparatus used was man- 
ufactured at its plant at Aldene, New 
Jersey, where it also manufactured radio 
parts, which it sold to amateurs and ex- 
perimenters in radio, while the equip- 
ment for its high power stations was pur- 
chased from the British Marconi Com- 
pany. 

There were only two other companies 
in the United States engaged in the op- 
eration of a radio communication service, 
the United Fruit Company and the Fed- 
eral Telegraph Company. The United 
Fruit Company, which operates a fleet 
of vessels in connection with its tropical 



fruit business between the United States, 
the West Indies, Central and South 
America, obtained a few radio patents 
and a license from the Marconi Company 
under certain of its patents. Its vessels 
were equipped with wireless apparatus 
and stations were erected in Boston, 
Massachusetts, New Orleans, Louisiana, 
and a few points in Central America from 
which a commercial service was main- 
tained. The Federal Telegraph Com- 
pany of California was organized in 1911 
and operated a ship-to-ship and ship-to- 
shore service on the Pacific Coast. 

Prior to the war, broadcasting for en- 
tertainment purposes had not been de- 
veloped and the radio apparatus required 
in receiving and transmitting sets were 
sold to the concerns engaged in the com- 
munication field, the United States Gov- 
ernment, and amateurs and experi- 
menters in the radio art. The principal 
manufacturers of apparatus and parts 
were the Marconi Company of America, 
Federal Telegraph Company, DeForest 
Radio, Telephone & Telegraph Com- 
pany, and the Wireless Specialty Ap- 
paratus Company, a subsidiary of the 
United Fruit Company. None of these 
concerns manufactured what is now 
termed the modern vacuum tube and 
which is considered so essential by the 
industry. Only the Marconi and De- 
Forest Companies manufactured vacuum 
tubes which because of certain defects 
were not considered of much importance. 

The DeForest Company manufactured 
tubes for only a short time since it was 
infringing the Fleming tube patents of 
the Marconi Company. The device 
then used for rectifying purposes was the 
crystal. Crystals and crystal receiving 
sets, efficient for short communication, 
were manufactured chiefly by the Wire- 
less Specialty Apparatus Company. The 
Federal Telegraph Company manufac- 
tured the Poulsen arc, which is used in 
high power stations, for its own use and 
sale to ship owners and the Government. 
The three important manufacturers of 
electrical apparatus, the General Electric 



Company, and the Westinghouse Elec- 
tric & Manufacturing Company, prior 
to the war did not sell radio apparatus, al- 
though they had done considerable re- 
search and development work. Some of 
the apparatus manufactured, however, 
was adapted for both radio and general 
electrical purposes. 

Radio Corporation 
Although engaged primarily in the 
manufacture of electrical machinery and 
apparatus, the subject of radio was of in- 
terest to the General Electric Company 
since many of its patents were also adapt- 
ed to the radio art. Among its develop- 
ments is the Alexanderson alternator, 
which is a machine for generating high 
frequency current, useful especially in 
long-distance communications. The first 
of these machines was installed in 1917 at 
the New Brunswick, N. J., station of the 
Marconi Company. Shortly thereafter 
the British Marconi Company com- 
menced negotiations for the exclusive 
rights to the machine but because of the 
war negotiations were suspended. After 
the signing of the armistice, negotiations 
were resumed but were practically con- 
cluded after a conference in April, 1919, 
between Rear Admiral Bullard, Director 
of Communication of the Navy, Com- 
mander S. C. Hooper, of Bureau of En- 
gineering of the Navy Department, and 
officials of the General Electric Company. 
The officials of the Navy Department 
suggested that an American radio cor- 
poration be formed to which the rights 
in the machine be sold and thus enable it 
to compete with British interests. A con- 
tract was proposed which provided for the 
organization of a company in such a man 
ner that the control thereof would re 
main in the control of American citizens 
At a conference in May, 1919, with of- 
ficials of the General Electric Company, 
Secretary Daniels stated (1) that he was 
in favor of government ownership of 
radio, which he intended to urge upon 
Congress, and (2) that he doubted his 
power to execute such a contract except 
with the consent of Congress. No such 



Why Not? 



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500 North Dearborn Street, 

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sound radio, up-to-date radio, useful radio, Practical radio. 

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P. S. Send along one of your free Reinartz booklets. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



39 




3 PREMIER I 



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authority was granted so the contract 
never became effective. The General 
Electric Company, therefore, began ne- 
gotiations for the purchase of the British 
Marconi Company's holdings in the Mar- 
coni Wireless Telegraph Company of 
America with a view of organizing a new 
company to carry on the radio business. 

The Radio Corporation of America 
was caused to be organized by the Gen- 
eral Electric Company, October 17, 1919. 
Its original capital stock was $1,000 but at 
the first meeting of the stockholders was 
increased to $25,000,000. On December 
31, 1922, there was outstanding 3,955,974 
shares, preferred stock, par value $5.00 
per share, and 5,734,000 shares common 
stock, no par value. Of this amount, the 
the General Electric Company owns 
1,875,000 shares, common, and 620,800 
shares, preferred; the Westinghouse Elec- 
tric & Manufacturing Company, 1,000,- 
000 shares, common and 1,000,000 shares, 
preferred; and the United Fruit Com- 
pany 160,000 shares, common, and 200,- 
000 shares, preferred. The remainder is 
held largely by the former stockholders of 
the American Marconi Company. The 
companies mentioned are represented on 
the Board of Directors with the Excep- 
tion of the American Telephone & Tele- 
graph Company. 

On November 20, 1919, the Radio 
Corporation entered into an agreement 
with the Marconi Wireless Telegraph 
Company of America, whereby the Radio 
Corporation issued to the Marconi Com- 
pany 2,000,000 shares of its preferred 
stock in exchange for the physical prop- 
erties, patents, licenses and good will of 
the Marconi Company. 

License Agreements 

The Radio Corporation has entered 
into agreements with the various com- 
panies which own or control practically 
all patents covering radio devices con- 
sidered of importance to the art. The 
number of patents involved approximates 
two thousand. Agreements of this char- 
acter have been entered into with the 
General Electric Company, Marconi's 
Wireless Telegraph Company, Ltd., 
American Telephone & Telegraph Com- 
pany and its subsidiary, the Western 
Electric Company, the United Fruit 
Company and its subsidiary, the Wire- 
less Specialty Apparatus Company, The 
International Radio Telegraph Com- 
pany, the Westinghouse Electric & Man- 
ufacturing Company, and the Radio En- 
gineering Company of New York. With 
certain minor limitations, the Radio 
Corporation under these agreements has 
secured an exclusive divisible right to sell 
and use the radio devices covered by the 
patents involved or by patents which 
these companies may acquire before the 
termination of the agreements. The 
agreements with the American Telephone 
& Telegraph Company and the Western 
Electric Company are to terminate in 
1930 while the remainder are to terminate 
in 1945. Provision is made for the mu- 
tual exchange of information relating to 
radio, and, in most instances the Radio 
Corporation has granted to the other 
company a license under its patents to 
make and use devices in the particular 




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40 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



field in which the other company is inter- 
ested. 

The Radio Corporation, under these 
agreements, is made the selling company 
for practically all radio devices to be sold 
the public under the hundreds of patents 
involved. The General Electric Com- 
pany and the VVestinghouse Electric & 
Manufacturing Company are to manu- 
facture and to sell to the Radio Corpora- 
tion only, these devices and apparatus, 
the Radio Corporation agreeing that 
sixty per cent of its annual requirements 
would be purchased from the General 
Electric Company and forty per cent from 
the Westinghouse Company. Until the 
expiration of the Fleming patents in 1922, 
the Radio Corporation had an absolute 
monopoly in the sale of vacuum tubes. 
On the expiration of these patents, the 
DeForest Radio, Telephone & Telegraph 
Company which had retained a right to 
manufacture and sell, commenced the 
sale of such tubes to the general public. 
In the sale of receiving sets, the Radio 
Corporation has competition from sev- 
enteen concerns licensed under the Arm- 
strong patents, although their sale of sets 
for use in conjunction with tubes is being 
contested in the courts at the present time. 

It is contended that their sale and use 
under the present patent situation con- 
stitutes an infringement of the tube 
patents of the Radio Corporation which, 
if upheld by the courts, will prevent all 
competition in the sale of complete sets, 
since the Western Electric Company is 
manufacturing and selling only trans- 
mitting apparatus for commercial pur- 
poses. 

Ship-to-Shore 

In communication by radio between 
ships at sea and the shore, the Radio 
Corporation is the dominant factor. Its 
chief competitors are the independent 
Wireless Telegraph Company, Ship Own- 
ers' Radio Service Company, Wireless 
Company of Port Arthur, and Gulf Radio 
Service operating on the Atlantic Coast 
and the Federal Telegraph & Telephone 
Company and the Kilbourne and Clark 
operating on the Pacific Coast. The ques- 
tion as to the right to use tubes, the pat- 
ents to which are under the control of the 
Radio Corporation, in apparatus fur- 
nished the ships and land stations is also 
involved in litigation, suit having been in- 
stituted by the Radio Corporation against 
the Independent Wireless Telegraph 
Company on this ground. The U. S. 
District Court for the Southern District 
of New York recently dismissed this bill 
for lack of parties since the DeForest 
Company, the owner of the patents in- 
volved and which had retained a personal 
license to make and sell, was a party to 
the proceeding in name only. If the con- 
tention of the Radio Corporation should 
finally prevail, competition from the other 
ship-to-shore service companies will be 
eliminated until there is a change in the 
patent situation. The Tropical Radio 
Telegraph Company, a subsidiary of the 
United Fruit Company, is also engaged 
in a ship-to-shore service in the Carribean 
Sea, but is affiliated with the Radio Cor- 
poration. 

Overseas Communication 

The Radio Corporation is the only 



concern now engaged in transmitting and 
receiving radio messages between the 
United States and foreign countries and 
contends that in order to function prop- 
erly it must of necessity secure a monop- 
oly in this field. The company has se- 
cured a virtual monopoly and controls all 
the high power stations with the excep- 
tion of those owed by the Government. 
In addition, it has entered into traffic 
agreements with the various foreign 
Governments and radio companies, the 
majority of these agreements providing 
that all messages intended for the United 
States shall be transmitted only through 
the facilities owned by the Radio Cor- 
poration of America. Agreements of this 
character have been made with Mar- 
coni's Wireless Telegraph Company, 
Ltd., covering the British possessions, and 
the Governments of Norway, Germany, 
France, Poland, Sweden and the Nether- 
lands. An agreement of a similar char- 
acter between the Marconi Company 
and the Japanese Government was as- 
sumed by the Radio Corporation when it 
purchased the assets of the Marconi 
Wireless Telegraph Company of America 
and traffic by radio between the countries 
established. 

In 1921, the Radio Corporation entered 
into an agreement with Marconi's Wire- 
less Telegraph Company, Ltd., a British 
concern, the Compagnie Generale de 
Telegraphie sans fil, a French concern, 
and the Gesellschaft Fuer Drahtlose 
Telegraphie m. b. H., a German con- 
cern, respecting radio traffic from South 
American countries which was afterwards 
extended to Central American countries. 
Steps have been taken to establish serv- 
ice between Brazil, Argentina, Columbia, 
Venezuela and the United States. This 
agreement was made subject to the rights 
of the United Fruit Company in Cuba, 
Colombia, the Panama Canal Zone and 
Central America, and its agreement with 
the Radio Corporation whereby it agreed 
not to establish or operate stations for 
wireless communication outside the al- 
lotted taritory. 

The Federal Telegraph Company of 
California, which is engaged in a ship-to- 
shore communication service on the Pa- 
cific Coast, in 1921 entered into a part- 
nership agreement with the Chinese Gov- 
ernment providing for the erection of 
stations in China and the establishment 
of a transoceanic service. This agree- 
ment was assumed by the Federal Tel- 
egraph Company of Delaware, which was 
organized by the old Federal Company 
and the Radio Corporation. An agree- 
ment between the various companies 
holding concessions in China was also 
proposed. The agreement was apparent- 
ly not executed and the correspondence 
with the Navy Department shows that 
the department would oppose any agree- 
ments of this character unless they were 
first approved by the respective govern- 
ments. In a letter to the Secretary of 
State dated December 16, 1921, Mr. 
Denby, Secretary of the Navy, em- 
phasizes the importance of maintaining 
competition in radio communication 
to and from China. The possibility of a 
monopoly in other fields than that of 
service is also pointed out, as is shown by 



the following excerpt from the letter: 

"The Navy Department fears that any 
commitment on the part of the Govern- 
ment to an arrangement favorable to a 
monopoly by a single commerical com- 
pany, though limited to a particular serv- 
ice, would but lend a means towards ex- 
tending monopoly to other services such 
as development and distribution of ap- 
paratus in general, and this is considered 
absolutely undesirable, particularly in 
the field of supply and service to ships." 

At the present time, the Radio Cor- 
poration has in operation communica- 
tion circuits with Great Britain, Norway, 
France, Germany, Poland, Italy and 
Japan. It is expected that the station 
in Sweden will be completed and ready 
for operation within the next six months 
and that the station near Buenos Aires, 
in the Argentine, will be completed in the 
near future. 

Because of the provisions in these 
various agreements providing for service 
through the facilities of the Radio Cor- 
poration exclusively, it is not believed 
that it will be possible for any other com- 
pany in the United States to conduct an 
efficient transoceanic service. In fact, a 
group of newspaper publishers in the 
United States who, sought to erect a sta- 
tion for the receipt of radio messages, 
after conducting experiments in this 
country, eventually built such a station at 
Dartmouth, Nova Scotia. This station 
is now being operated, its service being 
supplemented by virtue of an arrange- 
ment with the British Post Office. The 
following are members of the association 
operating such service: 

The Chicago Tribune. 

The New York Times. 

The New York World. 

The New York Herald. 

The New York Tribune. 

The Philadelphia Public Ledger. 

United Press Association of America. 

International News Service. 

Universal Service. 

The association is not exclusive and 
business for other newspapers is conduct- 
ed at a charge of one cent per word. 
Sale of Apparatus 

The refusal to sell or lease apparatus to 
competitors for international communica- 
tion purposes is included in the well de- 
fined policy of the Radio Corporation of 
America. It also affixes to the apparatus 
sold a license notice, the object of which 
is to restrict the purchaser's use of the 
device to amateur and experimental pur- 
poses. In supplying ships with ap- 
paratus, devices and appliances, the ship 
owners are required to execute an agree- 
ment which provides that the apparatus, 
etc., furnished by the Radio Corporation 
is licensed only for use on board ships and 
aircraft in communications destined to or 
originating on such ships or aircraft. 

The Radio Corporation distributes its 
products chiefly through wholesale con- 
cerns handling electrical supplies. In 
order for a distributor to handle these 
goods it must furnish evidence that it has 
the facilities for conducting a wholesale 
business and give an initial order amount- 
ing to not less than $25,000. Independent 
manufacturers of sets are not sold vacuum 
tubes and other patented devices for re- 



RADIO AGE— "THE MAGAZINE OP THE HOUR" 



41 



sale in connection with sets manufac- 
tured by them. This was a hardship, par- 
ticularly when there was a shortage of 
tubes, as the dealers were unwilling to 
furnish them with tubes. The investiga- 
tion shows that the shortage in tubes 
was confined to three of the six types 
manufactured and prevailed during 1922 
and first few months of 1923. There was 
a marked increase in the demand for tubes 
as the industry developed as is shown by 
the orders received by the Radio Cor- 
poration which were as follows: 1921, 
112,500; 1922, 1,583,021; and for the first 
nine months of 1923, 2,931,262 tubes. 
Although the officials of the Radio Cor- 
poration admit that they do not carry 




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dealers who confine their orders to tubes 
exclusively, there is little evidence that 
the Radio Corporation required dealers 
to handle their goods exclusively or 
favored such dealers, in the supply of 
tubes, as compared with dealers who also 
handled apparatus manufactured by 
others. 

The DeForest Radio, Telephone & 
Telegraph Company which is now en- 
gaged in the manufacture and sale of a 
modern vacuum tube, also a ffixes to its 
product notices with respect to use sim- 
ilar to those used by the Radio Corpora- 
tion. This company has recently adopt- 
ed the policy of making the distributors of 
its products, agents. 

The Commission submits no conclu- 
sions in this report as to whether the 
facts disclosed constitute a violation of 
the anti-trust laws, as the House resolu- 
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called only for the facts and data "as in 
the opinion of the Commission may aid 
the House of Representatives in deter- 
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Make Your Receiving Set Selective 



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Matthew P. Adams, superintendent of 
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for his flock of 1,200. 

Thomas Mulligan and Thomas Bur- 
gess, two important cogs on the Moose- 
heart lightweight foot ball team, each 
of whom suffered a broken leg in a game 
at Morris, 111., were removed to an 
Aurora hospital, both feeling fit as 
Punch but with heavy casts keeping 
them confined to their beds. After the 
fractures were reduced all they would 
have to do for six weeks would be to lie 
in bed — and on their backs. 

Superintendent Adams surprised the 
two lads when he had a radio receiving 
outfit installed in their room at the 
hospital. It is equipped with a quieting 
device so that other patients will not be 
disturbed, but the two Mooseheart boys 
have earpieces so that they get news, 
music and entertainment going on in the 
world without even turning over in bed. 

Every night they get scores of athletic 
contests, news of the day, concerts from 
all parts of the country and then the 
bed-time story and their red letter days 
were when university football games were 
broadcast, play by play. They need 
pay no attention to "lights out" or other 
usual hospital rules, for they get radio 
messages until the early hours of the 
morning unless they go to sleep. 

Mooseheart is the academic and voca- 
tional school of the Loyal Order of 
Moose for dependent children of deceased 
members. 




The Benson Melody Wave Trap elim- 
nates annoying interferences. It is the 
inductively coupled type with a high 
grade .001 mfd. variable condenser. Ail 
mounted in a beautiful leather covered 
cabinet with an engraved bakelite panel. 

Price $8.75 

BENSON MELODY CO. 

2125 No. Halsted CHICAGO, ILL 

Send 25c for a Benson Melody Radio "Trouble Finding" Cbarf 



Cold Winter 
Nights 

Won't find you on the roof fixing 
the aerial — removing snow and 
sleet, exposing yourself to sickness, 
if you use 




ANTENELLA 

(No aerial or antenna needed) 

A light socket plug that eliminates 
all outside wiring, lightning arrest- 
ers and other inconveniences. 
Merely plug Antenella in any light 
socket and you can enjoy the best 
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Now Only $1.25 

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eshmanfo.lnc. 

Condenser deducts 



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If your newsdealer has sold out 
his supply of RADIO AGE you are 
likely to miss just the hook-up that 
you have been looking for. To 
avoid any such chance fill out the 
coupon in this issue and send in your 
subscription. Then you will be safe. 
And don't forget that with each 
subscription at the special price of 
$2.00 a year, or $1.00 for six months, 
we send you free the popular Rein- 
artz Radio booklet FREE. Address 
Radio Age, 500 N. Dearborn Street, 
Chicago, 111. 



42 



RADIO AGE — "THE MAGAZINE OF THE HOUR" 



Turning on Our Loud Speaker 



SAY, Mr. Radio Bugg, are you a 
regular reader of RADIO AGE? 
Before you file this copy of RADIO 
AGE, stop a minute and think over 
what you found in it. Have you ever 
read articles as clear as the ones you just 
finished? Did you ever see drawings and 
circuits more clearly portrayed? Per- 
haps you have once or twice — but here's 
your opportunity to be assured of real 
practical information right along. 

Read over the following extracts and 
letters from our readers, who know and 
appreciate first-hand radio information; 
real practical radio. Here's a shining 
example of just what RADIO AGE has 
done for one of our readers and it shows 
how we can help you: 
RADIO AGE, 
Gentlemen: 

Being an admirer of RADIO AGE, 
I just built the three circuit receiving 
set designed by Felix Anderson as it was 
published in the November, 1923, issue 
of your publication. 

I have built nine different sets from 
supers to various other types of sets, 
published in other radio journals, and 
they turned out to be jokes. I won't 
mention the names of the other maga- 
zines but I will say that the sets I built 
came out of every radio journal I could 
buy, and I think I got them all. I was 
almost heartbroken, as it cost a pretty 
penny to be fooled like that. 

So I resolved I would try one more 
and I did, which was the above mention- 
ed set, and while I am writing this I feel 
like jumping up and down and holler- 
ing. 

You may publish this letter if you 
wish, as I think your readers would 
enjoy knowing that it is a feeling of great 
joy to know that at last one can get 
radio from a reliable source, and get 
information that is straight. 

This is the only way I know of express- 
ing my appreciation for such a book. 
Very truly yours, 

B. R. THOMPSON, 

731 West Congress Street, Chicago, 111. 

Ronald Cox, of Beach Haven, N. J., 
built one of the simple tubes sets des- 
cribed in RADIO AGE, writes as he en- 
closes a record breaking list of stations 
(see the Pickups section of this issue). 

"Your magazine is the best I have 
ever seen." 

Just read over this little extract from a 
letter of A. E. McElroy of Columbia, Mo. 

"I have been reading your magazine 
for the past several months, and I have 
been particularly attracted by the excep- 
tionally good, clear, and concise hookups 
you print." 

James P. Cooper of Memphis, Tenn., 
says: 

"I am proud to be a subscriber to 
your valued and instructive paper." 

John J. Drechsler of 2111 St. Paul 
Street, Baltimore, Maryland, writes us: 

"I have RADIO AGE to thank for 
the many days of pleasure I derived 
from my Kopprasch set. Gentlemen, 
kindly accept my humble thanks for 
your untiring labors." 

It's rather pleasant to believe that 
readers of RADIO AGE are as apprecia- 
tive as that! 



James E. Chandler of Belvidere, 111., 
says: 

"I am a regular reader of your good 
magazine, RADIO AGE, and I want 
to tell you that I find it most instructive 
and helpful." 

George Rollisson of 418 West Elm 
Street, Hanford, Calif., writes: 

"I have read nearly all the different 
radio journals and am proud to say that 
RADIO AGE beats them all when it 
comes to hookups and material." 



We get letters from fellows who have 
just started to read RADIO AGE which 
run something like this excerpt from the 
letter of F. M. Swissher of Meadowbrook, 
W. Va.: 

"If you keep making your issues like 
the November issue, then it is without 
doubt the best radio book ever pub- 
lished. Keep up the good work." 

There is no doubt about keeping up 
the good work. This month new writers 
appear on the staff of RADIO AGE, 
to furnish our interested fans with more 
and more first rate information. It's 
pretty hard to find a more capable staff 
of workers than Frank D. Pearne, Felix 
Anderson, Carl Masson, Arthur B. Mc- 
Cullagh, Carl Butman, John B. Rath- 
bun, J. A. Callanan, all doing their level 
best to supply you with first rate radio. 

The following is just another reason 
why you should be a regular RADIO 
AGE booster. Philip G. Shermerhorn 
of 67 West 52d Street, New York City, 
N. Y., tells us: 

"May I say that I send in my subscrip" 
tion, partly because of the excellen 1 - 



material composing your magazine, and 
partly because of the list of broadcast- 
ing stations, since this list is an absolute 
necessity to DX listeners." 

Perhaps as you glanced through the 
magazine you have noticed that we 
feature a list of broadcasting stations 

But our list is different — it is not only 
a list of stations — it is a corrected list, 
which is kept to date for each issue by 
special service and news bureaus, and 
by the watchful eye of our Washington 
correspondent. 

We hope you will pardon us for taking 
so much of your time, but we know that 
if we don't tell you about RADIO AGE, 
in this way, you'll probably never get 
to hear about it, because the average 
RADIO AGE reader is so busy copying 
long distance signals on a set made ac- 
cording to RADIO AGE instructions 
that he will just point to a magazine on 
his work bench, and mumble "LET 
THEIR HOOKUPS BE YOUR 
GUIDE." 



A Public Chat 

WJAZ, the Zenith-Edgewater Beacb 
Hotel broadcasting station, was re 
broadcasting an outside station the 
other night, the operator forgot to close 
his transmitter and a queer thing hap- 
pened. Some one called him up on the 
phone and had quite a conversation 
with him. Thousands of fans thought 
that they were hearing two broadcasting 
stations carrying on a conversation 
The caller's voice was just as clear as 
the operator's due to some freak of in- 
ductance. 



GIVEN FREE: 
REINARTZ BOOK 

Complete construction directions with Hook-ups — best book on 
good circuit — written and illustrated by Frank D. Pearne. If you 
want one free, fill out the coupon and send with your subscription 
remittance, $2.00 for one year. 



RADIO AGE, 

500 North Dearborn St., 

CHICAGO. 

Please send me FREE one of your Reinartz Radio Books and send 
me Radio Age for one year. I want to take advantage of this 
Special Offer. I enclose two dollars. 



Name.. 




RADIO AGE— "THE MAGAZINE OF THE HOUR' 



43 



Complete Corrected List of U. S. and Canadian 

Broadcasting Stations 



Complete Each Issue 

THE list of broadcasting stations on these pages is brought up to date each month by 
additions of new stations and deletion of those which have suspended operation. The list 
is the product of a vast volume of correspondence and its completeness is due in large 
measure to the assistance of our special news service in Washington, D. C. Suggestions, correc- 
tions and additional data will be welcomed from readers and broadcasters. 



KOKA 

KDPM 

KDPT 

KDYL 

KDYM 

KDYQ 

KDYS 

XDYW 

KDYX 

KDZB 

KDZE 

KDZF 

KDZI 

KDZK 

KDZQ 

KDZR 

KDZT 

KFAD 

KFAE 

KFAF 

KFAJ 

KFAN 

KFAP 

KFAR 

KFAU 

KFAV 

KFAW 

KFAY 

KFBB 

KFBC 

KFBE 

KFBG 

KFBK 

KFBL 

KFBS 

KFBU 
KFCB 
KFCD 
KFCF 
KFCH 
KFCK 
KFCM 
KFCP 
KFCV 
KFCY 
KFCZ 
KFDA 
KFDD 
KFDH 
KFDJ 
KFDL 
KFDO 
KFDR 
KFDU 
KFDV 
KFDX 
KFDY 

KFOZ 
KFEC 
KFEJ 
KFEL 
KFEP 
KFEQ 
KFER 
KFEV 
KFEX 
KFEY 
KFEZ 

KFFB 

KFFE 

KFFO 

KFFQ 

KFFR 

KFFV 

KFFX 

KFFY 

KFFZ 

KFGC 

KFGD 

KFGH 

KFGJ 

KFGL 

KFGQ 

KFGV 

KFGX 

KFGZ 

KFHA 

KFHB 

KFHD 

KFHF 

KFHH 

KFHJ 

KFHQ 

KFHR 

KFHS 

KFHU 

KFHX 

KFI 

KFIB 

KFID 

KFIF 

KFIK 

KFIL 

KFIO 

KFIQ 

KFIU 

KFIV 

KFIX 

KFIY 



Westinghouse Electrio & Mfg. Co _ 

Westinghouse Electrio & Mfg. Co 

Southern Electrical Co. _.. 

Telegram Publishing Co. . 

Savoy Theatre 

Oregon Institute of Technology. 

The Tribune... 



Smith Hughes & Co.. 

Star Bulletin 

Frank E. Siefert— _ 

The Rhodes Co. 



Wave 
length 

East Pittsburgh 326 

_ Cleveland, Ohio 270 

San Diego. Calif. 244 

-Salt Lake City, Utah 360 

San Diego. Calif. 252 

._ Portland, Oreg. 360 

Great Falls. Mont. 360 

.Phoenix. Ariz. 360 

..Honolulu. Hawaii 360 



Automobile Club of Southern California... 
Electric Supply Co... 



Bakersfleld. Calif. 240 

_ Seattle. Wash. 455 

.....Los Angeles, Calif. 278 

Wenatchee. Wash. 360 

Reno, Nev. 360 

Denver. Colo. 360 



Nevada Machinery & Electric Co.. 

Nichols Academy of Dancing 

Belllngham Publishing Co. Bellingham. Wash. 261 

Seattle Radio Assn. Seattle. Wash. 360 

McArthur Bros. Mercantile Co. . _ Phoenix, Ariz. 360 

State College of Washington..- .Pullman. Wash. 360 

Western Radl» Corp - . Denver. Colo. 360 

University of Colorad*..... Boulder, Colo. 360 

The Electric Shop Moscow, Idaho 360 

Standard Publishing Co. Butte, Mont. 360 

Studio Lighting Service Co. (O. K. OUen)...- Hollywood, Calif. 280 

Independent School District of Boise- City, Boise High School. Boise. Idaho 270 

Abbot Kinney Co. '. Venice, Calif. 224 

The Radio Den (W. B. Aahford) Santa Ana. Calif. 280 

W. J. Virgin Medford. Oreg 283 

F. A. Buttrey & Co. Havre, Mont. 360 

W. K. Azbill- _ San Diego. Calif. 278 



Reuben H. Horn.. 



..San Luis Obispo. Calif. 360 

Tacoma. Wash. 360 

Sacramento. Calif. 283 

Everett. Wash. 224 



First Presbyterian Church 

Kimball- Upson Co. _ 

Leese Bros. 

Trinidad Gas & Electric Supply Co. and the Chronicle News 

Trinidad, Colo. 360 

The Cathedral (Bishop N. S. Thomas) .Laramie. Wyo. 283 

Nielsen Radio Supply Co Phoenix. Ariz. 238 

Salem Electrio Co. (F. S. Barton)- Salem. Oreg. 360 

Frank A. Moore : Walla Walla. Wash. 360 

Electric Service Station (Inc.) Billings, Mont. 360 

Colorado Springs Radio Co._ _ Colorado Springs, Colo. 258 

Richmond Radio Shop (Frank T. Doelng) _ - -Richmond, Calif. 360 

Ralph W. Flygare Ogden, Utah 360 

Fred Mahaffey, Jr. Houston. Tex. 360 

Western Union College- LeMars. Iowa 252 

Omaha Central High School. Omaha. Nebr. 258 

Adler"g Muslo Store.... Baker, Oreg. 360 

St. Michaels Cathedral Boise. Idaho 252 



University of Arizona- 
Oregon Agricultural Cellege.. 
Knlght-Campbell Muslo Co. 
H. Everett Cutting 



-Tucson, Ariz. 360 

-CorvalUs. Oreg. 360 

Denver. Colo. 360 

..Bozeman. Mont. 248 

Bullock's Hardware & Sporting Goods (Robert G. Bullock). York. Nebr 360 

Nebraska Radio Electrio Co _ Lincoln, Nebr. 240 

Gilbrech & Stlnson .Fayetteville. Ark. 360 

First Baptist Church. Shreveport, La. 360 

South Dakota State College of Agriculture and Mechanic Arts. 

Brookings, S. Dak. 360 

Harry O. Iverson Minneapolis. Minn. 231 

Meier & Frank Co. Portland, Oreg. 360 

Guy Greason ™ .Tacoma. Wash. 360 

Winner Radio Corp. Denver, Colo. 360 

Radio Equipment Co. (Joseph L. Turre) Denver. Colo. 240 

J. L. Scroggin - Oak. Nebr. 360 

Auto Electric Service Co. - -Fort Dodge. Iowa 231 

Radio Electrio Shop Douglas. Wyo. 263 

Augsburg Seminary _ Minneapolis, Minn. 261 

Bunker Hill & Sullivan Mining & Concentrating Co Kellogg. Idaho 360 

American Society of Mechanical Engineers (F. H. Schubert.) 

St. Louis. Mo. 360 

Jenkins Furniture Co. . Boise. Idaho 240 

Eastern Oregon Radio Co .Pendleton. Oreg. 360 

Dr. E. H. Smith. Hlllsboro. Oreg. 229 

Marksheffel Motor Co. Colorado Springs, Colo. 360 

Nevada State Journal (Jim Kirk) - Sparks. Nev. 226 

Graceland College. Lamonl, Iowa 360 

McGraw Co Omaha. Nebr. 278 

Plncus & Murphy. Alexandria. La. 275 

Al. G. Barnes Amusement Co.— _ Dallas, Tex. (portable) 226 

Louisiana State University _ Baton Rouge. La. 254 

Chickasha Radio & Electric Co. Chlckasha. Okla. 248 

Lelanrt Stanford University _ _ Stanford University, Calif. 360 

Missouri National Guard. 138th Infantry St. Louis. Mo. 266 

Arlington Garage _ _ _ Arlington, Oreg. 234 

Crary Hardware Co. ..._ Roone, Iowa 226 

Heidbreder Radio Supply Co.— _ - _ Utica. Nebr. 224 

First Presbyterian Church _ Orange, Tex. 250 

Emmanuel Missionary College. _ Berrien Springs. Mich. 268 

Western State College of Colorado. _ „ Gunnison, Colo. 212 

Rlalto Theater (P. L. Beardwell) Hood River, Oreg. 280 

Utz Electric Shop Co. St. Joseph. Mo. 226 

Central Christian Church. _ _ Shreveport. La. 266 

Ambrose A. MoCue - _ Neah Bay. Wash. 283 

Fallon & Co Santa Barbara. Calif. 360 

Curtis Brothers Hardware Store (Alfred E. Fowler) -Los Gatos. Calif. 242 

Star Electric & Radio Co _ _ Seattle. Wash. 270 

Clifford J. Dow - _ _. Llhue. Hawaii 275 



M. G. Sateren. _ _ Mayrille. N. Dak. 

Robert W. Nelson - _ _ _ Hutchinson. Kans. 

Earle C. Anthony (Inc.) _ Los Angeles. Calif. 



261 
229 
469 



-St. Louis. Mo. 244 
246 



Franklin W. Jenkins 

Ross Arbuckle's Garage _ lola. Kans. 

Benson Polytechnic Institute _ _ Portland. Oreg. 360 

Oladhrook Electrical Co _ Oladbrook. Iowa 234 

Winrtisch Electric Farm Equipment Co. Loulshurg. Kans. 234 

North Central High School _ - ...Spokane, Wash. 252 

Yakima Valley Radio Broadcasting Association Yakima. Wash. 224 

Alaska Electrio Light & Power Co Juneau. Alaska 226 

V. H. Broyles _ _.._ Pittsburg. Kans. 240 

Reorganized Church of Jesus Christ of Latter Day Saints 

Independence. Mo. 240 

Brott Laboratories Seattle. Wash. 236 



KFIZ Dally Commonwealth and Oscar A. Huelsman .Fond du Lac, Wis. 273 

KFJA Central Power Co Grand Island, Nebr 244 

KFJB Marshall Electrical Co. Marahalltown, Iowa 248 

KFIC SeatUa Post Intelligencer. Seattle. Wash. 233 

KFJD Weld County Printing & Publishing Co Greeley. Colo. 236 

KFJF National Radio Manufacturing Co. Oklahoma City, Okla. 252 

KFJH "The Sugar Bowl" (H. R. Shaw).— Selma, Calif. 273 

KFJI Liberty Theatre (E. E. Marsh) Astoria. Oreg. 252 

KFJJ Carrollton Radio Shop .Carrollton. Mo. 236 

KFJK Delano Radio and Electric Co. Bristow. Okla, 23S 

KFJL Hardsacg Manufacturing Co. Ottumwa. Iowa 242 

KFJM University of North Dakota Grand Forks. N. Dak. 229 

KFJR Ashley C. Dixon & Son.— Stevensvllle. Mont, (near) 258 

KFJU Central Power Co Kearney. Nebr. 234 

KFJV Thomas H. Warren - -. Dexter. Iowa 224 

KFJW Le Grand Radio Co Towanda. Kans. 229 

....Cedar Falls. Iowa 229 



KFJX Iowa State Teachers' College. _ 

KFJY Tunwall Radio Co Fort Dodge. Iowa 249 

KFJZ Texas National Guard. One hundred and twelfth Cavalry Fort Worth. Tex. 254 

KFKA Colorado State Teachers College Greeley, Colo. 248 

KFKB Brinkley- Jones Hospital Association Jlilford. Kans. 288 

KFKH Denver Park & Amusement Co _ .Lakeside. Colo. 226 

KFKQ Conway Radio Laboratories (Ben H. Woodruff) Conway. Ark. 224 



KFKV F. F. Gray 



-Butte. Mont. 283 
288 



KFKX Westinghouse Electric & Manufacturing Co. Hastings. Nebr. 

KFKZ Nassour Bros. Radio Co Colorado Springs. Colo. 234 

KFLA Abner R. Willson... _ _ —.Butte. Mont 283 

KFLB Signal Electric Manufacturing Co. .Menominee. Mich. 248 

KFLD Paul E. Greenlaw Jrankllnton. La, 234 

KFLE National Educational Service. .Denver, Colo. 269 

KFLH Erlckson Radio Co. Salt Lake City. Utah 261 

KFLP Everette M. Foster ___.Cedar Rapids, Iowa 240 

KFLQ Blzzell Radio Shop _ Little Rock. Ark. 261 

KFLR University of New Mexico. _ Albuquerque. N. Mex. 254 



KFLU Rio Grande Radio Supply House. 

KFLV Rev. A. T. Frykman „.. 

KFLW Missoula Electric Supply Co. 

KFLZ Atlantic Automobile Co 

KFMQ University of Arkansas 

KFMR Morningside College 

KGB Tacoma Dally Ledger. 



-San Benito. Texas 238 

RocMord. I1L 229 

Missoula. Mont. 234 

Atlantic. la. 273 

...Favetteville. Ark. 263 



KGG 

KGN 

KGU 

KGW 

KGY 

KHJ 

KHQ 

K1Q 

KIR 

K1S 

KLN 

KLS 

KLX 

KLZ 

KMJ 

KMO 

KNT 

KNV 

KNX 

KOB 

KOP 

KPO 

KQI 

KQP 

KQV 

KQW 

KRE 

KSD 

KSS 

KTW 
KUO 
KUS 
KUY 
KWG 
KWH 
KXD 
KYQ 
KYW 
KZM 
KZN 
KZV 



Sioux City. Iowa 261 

—.Tacoma. Wash. 252 

Hallock & Watson Radio Service. Portland. Oreg. 369 

Northwestern Radio Mfg. Co _ Portland, Oreg. 369 

Marlon A. Mulrony .Honolulu. Hawaii, Waikikl Beach. 360 

Portland Morning Oregonlan —Portland, J)reg. 492 



St. Martins College (Rev. Sebastian Ruth). 
Times-Mirror Co „ _._ 

Louis Wasmer - — . 

C. O. Gould 



Northwest Radio Service Co 

Bible Institute of Los Angeles.. 
Monterey Electric Shop 



..Lacy Wash. 258 

...Los Angeles. Calif. 395 

._ —.Seattle, Wash. 360 

-.Stockton, Calif. 360 

-Seattle. Wash. 270 



Warner Brothers Radio Supplies Co... 

Tribune Publishing Co „ _. 

Reynolds Radio Co . 

San Joaquin Light & Power Corp... 



_Xos Angeles. Calif. 369 

.Monterey, Calif. 261 

Oakland. Calif. 360 

Oakland, Calif. 360 

Denver, Colo. 360 

.... .Fresno, Calif. 273 



Love Electric Co _ - .Tacoma. Wash. 369 

Grays Harbor Radio Co. (Walter Hemrlch).— _ Aberdeen, Wash. 263 

Radio Supply Co _ —Los Angeles, Calif. 258 

Electric Lighting Supply Co _ _ _ Xos Angeles. Calif. 360 

New Mexico College of Agrloulture & Mechanic Arts 

State College. N. Mex. 360 

Detroit Police Department _ Detroit. Mich. 288 

Hale Bros San Francisco. Calif. 423 

University of California.— Berkeley. Calif. 360 

Apple City Radio Club Hood River. Oreg. 360 

Doubleday-Hill Electrio Co Pittsburgh. Pa. 360 

Charles D. Herrold _ San Jose. Calif. 360 

Berkeley Daily Gazette .Berkeley. Calif. 278 

Post Dispatch (Pulitzer Pub. Co.) - St. Louis, Mo. 546 

Prest & Dean Radio Co. and Radio Research Society of Long Beach. 

Calif -Long Beach. Calif. 369 

First Presbyterian Church _. — Seattle. Wash. 



Examiner Printing Co.. 



380 

San Francisco. Calif. 369 

City Dye Works & Laundry Co _ Xos Angeles, Calif. 360 

Coast Radio Co .El Monte. Calif. 258 

Portable Wireless Telephone Co Stockton. Calif. 369 

Los Angeles Examiner. _ _ Los Angeles, Calif. 399 

Modesto Herald Publishing Co... Modesto. Calif. 252 

Electric Shop _ _ Honolulu. Hawaii 369 

Westinghouse Electric & Mfg. Co Chicago. 111. 539 

Preston D. Allen _ Oakland. Calif. 369 

The Deseret News Salt Lake City. Utah 369 

Wenatchee Battery & Motor Co Wenatchee. Wash. 369 

WAAB Valdemar Jensen New Orleans. La, 288 

WAAC Tulane University _ _ New Orleans. La. 368 

WAAD Ohio Mechanics Institute Cincinnati. Ohio 369 

WAAF Chicago Dally Drovers Journal 

WAAK Glmbel Brothers 

WAAM I. R. Nelson Co 

WAAN University of Missouri 



WAAW Omaha n-aln Exchange 

WAA7 Holllster- Miller Motor Co 

WAR A Ijike Forest College 

WA8B I>r. John B. Lawrence 



..Chicago. Til. 286 

_ -.Milwaukee. Wis. 289 

263 
254 
366 



Newark, N. J. 

- Cnlunihla, Mo, 

Omaha. Nebr. 

Emporia. Kans. 869 

...Lake Forest. 111. 266 

Harrisburg, Pa. 269 

WABC Fulwlder-C.rlmes Battery Co.— - Anderson. Ind. 229 



WABD Parker High School _ Dayton. Ohio 283 

WABE Yonng Men's Christian Association _ Washington. D. C. 283 

WABF Mount Vernon Register-News Co - .Mount Vernon, Til. 234 

WABG Arnold Edwards Piano Co _ _ Jacksonville, Fla. 248 

WABH Lake Shore Tire Co. _ Sandusky, Ohio 249 

WABI Bangor Rallwav & Electrio Co _ Bangor, Mc. 249 

WAB1 The Rarllo Laboratories _ South Bend. Tnd. 249 

WABK First Baptist Church _ _ Worcester. Mass. 252 

WABL Connecticut Agricultural College Storrs. Conn. 283 

WABM F. E. Doherty Automotive and Radio Equipment Co Saginaw. Mich. 254 

WABO Waldo C. Orover _ La Crosse, Wis. 244 

WABO Lake Avenue Baptist Church _ _ Rochester. N. Y. 252 

WABP Robert F. Welnlg _ „ Dover, Ohio 268 

WART TTolldav-TTall. Radio Engineers — Washington. Pa. 252 

WARU Victor Talking Machine Co - _ — Can.den. N. J 



WARV John H. DeWltt. Jr.. 
WRAA Purdue University.. 



229 
..JJashvllle. Tenn. 293 



_ - West Layayette. Ind. 

WBAD Sterling Electric Co - Minneapolis. Minn. 



369 
360 



44 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



Pickups by Readers 



(Continued from page 20.) 
Gentlemen: 

In this November RADIO AGE you 
have a letter sent in by Frank A. Flecken- 
stein, Memphis. According to his record 
he has heard twenty-two stations in 
nine days with his Cockaday. You ask 
if his record can be beaten in the same 
period of time. Here is my record, and 
let me state now that I keep two pairs 
of receivers hooked up to my set, and 
when I get a distant station I have my 
mother or a visitor to listen in on them 
long enough to prove that I am getting 
them. For practically all these stations 
I have such proof. 

I have a single circuit set using the 
two-variometer hookup of the Aeriola 
portable set, and / have only the detector. 
From the twenty-seventh of October to 
the seventh of November I used my set 
nine nights (closed down on November 
3, 4 and 5 on account of discharged A 
battery). Here is the list; a total of 
forty-seven stations: 

KDKA, Pittsburgh, KFKB, Melford, 
Kan.; KSD, St. Louis; KOP, Detroit; 
KYW, Chicago; WAAP, Wichita, Kan.; 
WBAP, Fort Worth; WDAF, Kansas 
City; WDAP, Chicago; WFAA, Dallas, 
Texas; WGY, Schenectady; WHAS, 
Louisville, WHAZ, Troy, N. Y.; WLW, 
Cincinnati; WMC, Memphis; WOC, 
Davenport; WSB, Atlanta; WWJ, 
Detroit; WSY, Montgomery, Ala.; 
WJAR, Providence, R. I.; 2XT, (?); 
9CD, Chicago, 111. WJAZ, Chicago; 
WCAP, Washington, D. C; WOAW, 
Omaha; WGR, Buffalo; (?), Erie, Penn- 
sylvania; WBAH, Minneapolis; WOR, 
Newark; (?), Columbus, Ohio; WSAI, 
Cincinnati; (?), Illinois University; 
WJAN, Peoria, 111.; WOAI, San Antonio, 
Texas; WHAM, Rochester; WHB, Kan- 
sas City; WJAX, Cleveland; WIAS, 
Burlington, La.; WMAQ, Chicago; 
KHJ, Los Anegles, (heard for nearly one- 
half hour on three successive nights); 
CHBC, Calgary, Canada; WHN, Brook- 
lyn; WTAM, Cleveland; WLAG, 
Minneapolis; WOS, Jefferson City, Mo.; 
WDAR, Philadelphia; WJAK, Green- 
town, Ind. f» 

These stations were received on a 
tuner wound on an oats box, a well- 
known and widely used article in rado 
construction with a UV200 detector 
tube and 2,000 ohm phones. Practically 
all my listening has been done between 
the hours of eight and midnight. Mr. 
Jeffers, in the letter following Mr. Fleck- 
enstein's, says he finished at 3:20 a. m. 
I got KHJ all three times between ten- 
thirty and eleven, although I have heard 
that one must wait until everything else 
has closed for the night before trying for 
the western coast. 

Very truly yours, 

LLOYD E. FOLTZ. 

It looks like you were getting the rasp- 
berry, Mr. Fleckenstein. Mr. Foltz cer- 
tainly has a mean way of snatching the 
long distance stations out of the air. 



Read for yourself: 

Beach Haven, N. J. 
RADIO AGE, 

Pickups Department. 
Gentlemen: 

I made a set according to your descrip- 
tion in the October RADIO AGE. 
It's a one-tube set described in "How 
to make your first tube set," and I want 
to say that it works fine. 

The first two nights I had it working 
I received the following stations: 

WHAS, Louisville, Ky., WSB, Atlanta 
Ga., WGY, Schenectady, N. Y., WJAX 
Cleveland, O., KSD, St. Louis, Mo. 
KYW, Chicago, 111., 6KW, Cuba, PWX 
Havanna, Cuba, WIP, Philadelphia 
Pa., WCAP, Washington, D. C, WHB 
Kansas City, Mo., WNAC, Boston 
Mass., WJAN, Peoria, 111., WGR 
Buffalo, N. Y., WJZ, New York, N. Y. 
WJAZ, Chicago, 111., WDAP Chicago 
III., 8XD, Ohio, WOO Philadelphia 
Pa., WBZ, Springfield, Mass., KDKA 
Pittsburgh, Pa., WLW, Cincinnati, Ohio 
WDAF, Kansas City, Mo., WPAD 
Chicago, 111., WCAE, Pittsburgh, Pa. 
WEAF, New York City, N. Y. WDAR 
Philadelphia, Pa., WOS, Jefferson City 
Mo., WWJ, Detroit, Mich., WOC 
Davenport, Iowa, WSAI, Cleveland 
Ohio, WPAM, Kansas City, Mo., WTAM 
Cleveland, Ohio. WEAM, Providence 
R. I., WNAP, Ohio, WCBD, Zion, 111 
III., WDAH, El Paso, Texas, WMAQ 
Chicago, I1L, a total of forty stations in 
two nights. 

Yours truly, 

RONALD COX. 

This looks like a real DX record, and 
it looks like the best list we have this 
month! Consider receiving forty sta- 
tions in two nights with a set composed 
of about eight or ten pieces or wireless 
instruments! We'll bet Mr. Cox will be 
able to hear a fly crawl on the wall down 
in the Hawaiian Islands broadcasting 
station when he adds a two-stage ampli- 
fier. Considering the type of set this 
little "flivver" is, we acclaim Mr. Cox 
the record holder for this month, and 
dare the rest of you to try and come 
up to it. By gum! You'd think it was 
a list taken off the log of a ten-tube super- 
heterodyne. Congratulations, Mr. Cox. 



In regard to this little DX getter» 
George Bindler, of Council Bluffs, Iowa, 
writes: 

"Mr. Anderson's set published in the 
October issue is certainly a dandy. I 
built one for my father." 

A little set of this type certainly makes 
a welcome gift, as it is easy to operate, 
more easy to understand, and least ex- 
pensive to keep up. Tell your father to 
let us have his list of stations heard with 
this little set of his, Mr. Bindler. 



looked good to me and I tried it. After 
assembling everything in shipshape order 
I tried it out. Did it work? Well, I'lt 
say it did! It brought in the following 
stations the first three days: WOC, 
Davenport; WDAP, Chicago; WJAZ, 
Chicago; KSD, St. Louis; WOAW, 
Omaha; WGY, Schenectady; KDKA, 
East Pittsburgh; WOS, Jefferson City; 
WFAA, Dallas; WABE, Washington, 
D. C; WBAP, Fort Worth; WSAI, 
Cincinnati; WLW, Cincinnati and WSB, 
Atlanta. 

How is that for getting 'em? I'll say 
it is the best little one-tube set I have 
ever had and I have had lots of them. 
It pretty nearly equals the results of my 
five-tube Reinartz. The Reinartz is a 
great set for distance and amplification. 
I don't believe I would trade my old 
Reinartz for any other set made; that is 
how I like them. 

Yours very truly, 

W. L. CARROLL. 

F'eaven sake! That little one-tube 
set must be a whiz if it's good enough to 
compare its reception records with a' five- 
tube Reinartz! Considering the amount 
of apparatus used, we'll bet Mr. Carrol 
is willing to concede that the little one- 
tube flivver beats his Reinartz! From 
what we know, the fellows get to love 
their Reinartz sets like a shipwrecked 
sailor loves a floating spar! Ask some 
of the radio widows whose husbands 
have Reinartz sets. 



And 6ay, fellows — do you know that 
our little "first tube set" described by 
Mr. Anderson in the October issue has 
enabled beginners to get into the real 
DX game! That little set is doing some 
real work. 



Now tune in on this one from the 
Virginia Hotel, Quincy, 111. 

RADIO AGE, 

Pickups Department, 
Gentlemen: 

In last month's RADIO AGE there 
was a circuit showing the amateur how 
to make his first tube set. This circuit 



If the foregoing two letters don't con- 
vince you as to the effectiveness of the 
"first tube set," read this one from 
4840 North Lincoln Street, Ravenswood, 
Chicago, 111., and weep: 
RADIO AGE, 

Pickups Department. 
Gentlemen: 

Just a few words to tell you that 1 
made the hookup given on page five of 
the October issue into a common little 
wooden box given me by a druggist, 
using for the panel nothing else than the 
wood of one side of the box and connect- 
ing all the units of the circuit with 
common bell wire. There is not a solder- 
ed joint in the set. On the road as a 
traveling man, I am getting all kinds of 
DX stuff with this set, in hotel rooms at 
night using sometimes a lighting socket 
plug, but more often the bed spring for 
an antenna and ground wire to a common 
water faucet. 

In Wisconsin towns have heard Buffalo, 
East Pittsburgh, Detroit, Chicago, and 
many others. Last night had KFKX of 
Hastings, Nebr., very loud and clear 
off the bed spring in this hotel. (Jeffer- 
son House, Jefferson, Wis.) 

No one need hesitate to build this set, 
for a flivver to carry around. There is 
not a night that I use it but what I get 
something satisfactory from some direc- 
tion, and real DX, using either of the 
above antenna systems. 

Yours very truly, 
A. J. BAUMGARDNER. 

At this point, the owners of eight and 
ten-tube reflexes, Reinartzes, Cockadays, 
Superheterodynes, etc., will plug in 
(Continued on page 46.) 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



45 



Complete Corrected List of U. S. and Canadian 

Broadcasting Stations 



WBAH The Dayton Ct.. 



.Minneapolis. Minn. 4 1 7 

.- Paterson. N. J. 244 

Decatur. 111. 360 



WBAN Wireless Phone Csrp _.. 

WBAO James Mlllikln University 

WBAP Wortham-Carter Publishing Co. (Star Telegram) Fort Worth. Tex. 476 

WBAV Erner & Hopkins Co _ Columbus. Ohio 390 

WBAW Marietta College ....Marietta. Ohio 246 



WBAX John H. Stenger. Jr. 
WBAY Western Electric Co... 



WBBA Newark Radio Laboratories 

WBBD Barbey Battery Service 

WBL T & H Radio Co— 



Pennsylrania State Police.. 

D. W. May. Ino 

Southern Radio Corp. 



....Wilkes- Barre, Pa. 360 

....New York. N. Y. 492 

Newark. Ohio 240 

.Reading. Pa. 234 

Anthony, Kans. 261 

Butler. Pa. 286 

Newark. N. J. 360 

..Charlotte. N. C. 360 



WBR 
WBS 
WRT 

WBZ Westlnghouse Elec. & Mfg. Co. _ Springfield, Mass. 337 

WCAD St. Lawrence University Canton. N. Y. 280 

WCAE Kaufuiann & Baer Co Pittsburgh. Pa. 462 

WCAG Clyde B. RandalL New Orleans. La. 268 



WCAH Entrekln Electrlo Co..: 

WCAJ Nebraska Wesleyan Unlverslty.. 
WCAK Alfred P. Daniel 



..Columbus, Ohio 286 
..University Place, Nebr. 360 

Houston, Tex. 360 

Northfleld. Minn. 360 

i Villanova, Pa. 360 

..Baltimore, Md. 360 
469 
360 
246 



WCAL St. Olaf College.. 

WCAM Villanova College 

WCAO Sanders & Stayman Co.- 

WCAP Chesapeake & Potomac Telephone Co. - Washington, D. C, 

WCAR Alamo Radio Electric Co. . San Antonio, Tex, 

WCAS William Hood Dunwoody Industrial Institute Minneapolis. Minn. 

WCAT South Dakota State School of Mines. Rapid City. S. Dak. 240 

WCAO Durham & Co -....Philadelphia. Pa. 286 

WCAV J. C. Dice Electrlo Co. -Little Rock, Ark. 360 

WCAX University of Vermont. Burlington. Vt. 360 

WCAY Kesselinan O'Drlscoll Co. . ._ .Milwaukee, Wis. 26 

WCAZ Carthage College ; Carthage, I1L 246 

WCBA Charles W. Helmbach 

WCBD Wilbur G. Voliva. 

WCE Findley Electric Co. 

VVCK Stlx, Baer & Fuller Dry Goods Co... 

WCM University of Texas. 

WCX Detroit Free Press... 



-Allentown. Pa. 280 
..Zlon, I1L 345 



WDAE Tampa Daily Times.. 
WDAF Kansas City Star.. 



WD AG J. Laurance Martin _ 

WDAH Trinity Methodist Church (South).. 

WDAK The Courant. 

WDAL Florida Times-Union. 

WDAO Automotive Electrlo Co 

WDAP Board of Trade... 



..Minneapolis, Minn. 360 

St. Louis. Mo. 360 

Austin. Tex. 360 

Detroit. Mich. 517 

Tampa. Fla. 360 

.Kansas City, Mo. 411 



...Amarillo. Tex. 263 

El Paso, Tex. 268 

Hartford, Conn. 261 

..Jacksonville, Fla. 360 



WDAR Lit Brothers 

WDAS Samuel A Walte 

WDAU Slooum Kllburn... 



..Dallas. Tex. 
-Chicago, 111. 



360 
360 

_ —Philadelphia.' Pa. 395 

..Worcester. Mass. 360 

New Bedford, Mass. 360 

WDAX First National Bank (Appamooso County Farm Bureau) 

Centerville, Iowa 360 

WDAY Radio Equipment Corp ! .Fargo. N. Dak. 244 

WDBC Kirk, Johnson & Co. ; Lancaster, Pa. 258 

WDM Church of the Convenant Washington. D. C. 360 

WDT Ship Owners Radio Service. New York. N. Y. 405 

WDZ James L. Bush .Tuscola, 111., Star Store Bldg. 278 

WEAA F. D. Fallaln Flint. Mich. 280 



WEAF American Telephone & Telegraph Co 

WEAH Wichita Board of Trade 

WEAI Cornell University— . 

WEAJ University of South Dakota - Vermilion, S. Dak. 283 



..New York. N. Y. 492 

Wichita, Kans. 244 

..Ithaca. N. Y. 286 



WEAM Borough of North Plalnfleld (W. Gibson Buttfield) 

..—North Plalnfleld. N. J. 252 

WEAN Shepard Co.— Providence. R. I. 273 

WEAO Ohio State University Columbus, Ohio 360 

WEAP Mobile Radio Co Mobile. Ala. 360 

WEAR Baltimore American & News Publishing Co Baltimore. Md. 360 

WEAS Hecbt Co __ Washington. D. C. 360 

WEAU Davidson Bros. Co. Sioux City, Iowa 360 

WEAY Iris Theatre (Will Horowitz. Jr.) - Houston. Tex. 360 

WEB Benwood Co.— St. Louis. Mo. 360 

WEV Hurlburt-SUll Electrical Co. Houston, Tex. 360 

WEW St. Louis University St. Louis. Mo. 261 

WFAA Dallas News & Dallas Journal _ Dallas. Tex. 476 

WFAB Carl F. Woese. : Syracuse. N. Y. 234 

WFAF H. C. Spratley Radio Ce. Pqushkeepsie. N. Y. 360 



WFAH Electrlo Supply Co.. 

WFAJ Hi-Grade Wireless Instrument Co.... 

WFAM Times Publishing Co... 



Port Arthur. Tex. 236 

-Ashevtlle, N. C. 360 

St. Cloud. Minn. 360 

Hutchinson. Minn. 380 



WFAN Hutchinson Electric Service Co. _ 

WFAQ Missouri Wesleyan College Cameron. Mo. 360 

WFAT Dally Argus-Leader. _ - Sioux Falls. S. Dak. 360 

WFAV University »f Nebraska. Department of Electrical Engineering 

„_ Lincoln. Nebr. 275 

WFI Strawbrldge & Clothier _ Philadelphia, Pa. 395 

WGAL Lancaster Electrlo Supply & Construction Co Lancaster, Pa. 248 

WGAN Cecil E. Lloyd— _ Pensacola. Fla. 368 

WGAQ Glenwood Radio Corp. (W. G. Patterson) Shreveport. La. 360 

WGAW Ernest C. Albright - Altoona. Pa. 261 

WGAY Northwestern Radio Co Madison. Wis. 360 

WGAZ South Bend Tribune - South Bend. Ind. 360 

WGI American Radio & Research Corp _ Medford Hillside. Mass. 360 

WGL Thomas F. J. Howlett _ Philadelphia. Pa. 360 

WGR Federal Telephone & Telegraph Co.- _ Buffalo. N. Y. 319 

WGV Interstate Electrlo Ce New Orleans. La. 360 

WGY General Electrlo Co Schenectady. N. Y. 380 

WHA University of Wisconsin _ Madison, Wis. 360 

WHAA State University of Iowa _ Iowa City. Iowa 283 

WHAB Clark W. Thompson Galveston. Tex. 360 

WHAC Cole Bros. Electrle Co _ Waterloo. Iowa 360 

WHAD Marquette University — Milwaukee. Wis. 280 

WHAG University of Cincinnati . Cincinnati. Ohio 222 

WHAH Harer Supply Co Joplln. Mo. 283 

WHAI Radio Equipment & Mfg. Co. Davenport. Iowa 360 

WHAK Roberts Hardware Co _ Clarksburg, W. Va. 258 

WHAM University of Rochester (Eastman School of Music) Rochester, N. Y. 283 

WHAP Otta & Kuhns _ —Decatur, 111. 360 

WHAR Paramount Radio & Electric Co. (W. H. A. Pulus) 

_ _ Atlantic City, N. J. 231 

WHAS Courier-Journal & Louisville Times LoulsvilN. Ky. 400 

WHAV Wilmington Electrical Specialty Co. „ Wllmlngtoh, Del. 360 

WHAZ Rensselaer Polytechnic Institute _ Troy. W. Y. 380 

WHB Sweeney School Co Kansas City, Mo. 411 

WHK Radlovox Co. (Warren R. Cox) Cleveland. Ohio 360 

WHN George Schubel New Ynrlt. N. Y. 360 

WIAB Joslyn Automobile Co.— _ _ Rockford. 111. 252 

WIAC Galveston Tribune.— Galveston. Tex. 360 

WIAD Howard R. Miller Ocean City. N. J. 254 

WIAF Gustav A. DeCortln New Orleans. La. 234 

WIAH Continental Radio & Mfg. Co. _ _ Newton. Iowa 258 

WIAI Heer Stores Co _ Springfield, Mo. 252 

WIAJ Fox River Valley Radio Supply Co. (Qulnn Bros.) Neenah. Wis. 224 

WIAK Journal-Stockman Co _ Omaha. Nebr. 278 

WIAO School of Engineering of Milwaukee .Milwaukee, Wis. 360 

WIAQ Chronicle Publishing Co Marlon. Ind. 226 

WIAR Paducah Evening Bun. Paducah, Ky. 360 



WIAS 
WIAT 
WIAU 
WIK 

WIL 

WIP 

WJAB 

WJAD 

WJAF 



-Burlington, Iowa 380 



Home Electric Co. 

Leon T. NoeL __ __ Tarklo. Mo. 360 

American irust & Savings Bank _ _ Le Mars. Iowa 360 

Ji. & L. Electric Co. (Herbert F. Kelso and Hunter J. Lohman) 

„ ' „ . .- _, . . „ , _ McKeesport, Pa. 234 

Continental Electric Supply Co Washington. D. C. 360 

Gimbel Brothers. Philadelphia, Pa. 509 

American Electric Co. _ Lincoln. Nebr. 360 

360 



Jackson's Radio Engineering Laboratories- 
Press Publishing Co _ 

WJAG Norfolk Daily News (Huso Pub Co.) 

WJAK Clifford L. White 

D. M. Perham _ ____!_ 

Peoria Star 

Capper Publications. 



WJAM 

WJAN 

WJAQ 

WJAR 

WJAS 

WJAT 

WJAX 

WJAZ 

WJD 

WJH 

WJX 

WJY 

WJZ 



Waco, Tex, 

Muncie, Ind. 360 

Norfolk. Nebr. 360 

..Greentown, Ind. 254 



-Cedar Rapids, Iowa 268 
..Peoria, 111. 280 



The Outlet Co. (J. Samuels & Bro.)_ 

Pittsburgh Radio Supply House 

Kelly-Vawter Jewelry Co. 

Union Trust Co 

Chicago Radio Laboratory 

Richard H. Howe _ 

W. P. Boyer- 



..Topeka, Kans. 360 



Deforest Radio Telephone & Telegraph Co"--.— 
R.' 



C. A— 



WKAA H. F. Paar 

WKAD Chas. Looff (Crescent Park). 

WKAF W. S. Radio Supply Co.... 

WKAN United Battery Service Co . 

WKAP Dutee W. Flint. 



Providence. R. I.' 360 

Pittsburgh. Pa. 360 

Marshall, Mo. 360 

Cleveland, Ohio 390 

Chicago, 111. 448 

Granville, Ohio 229 

-Washington, D. C. 273 

New York, N. Y. 360 

New York, N. Y. 408 

-New York, N. Y. 455 



WKAQ Radio Corp. of Porto Rico. 

WKAR Michigan Agriculture College. 

WKAS L. E. Lines Music Co 

WKAV Laconia Radio Club _ _ 

WKAW Turner Cycle Co „. 

WKAY Brenau College _ 

WKY WKY Radio Shop.. 



WLAG Cutting & Washington" Radio" Corp" ■••- 

WLAH Samuel Woodworth 

WLAJ Waco Electrical Supply Co — 1'"' 

WLAK Vermont Farm Machine Corp 

WLAL Naylor Electrical Co _ _ 

WLAN Putnam Hardware Co. _. 

WLAP W. V. Jordon 

WLAQ Arthur E. Schilling. 



Cedar Rapids. Iowa 268 

-East Providence, R. I. 240 

— Wichita Falls. Tex. 360 

- Montgomery, Ala. 226 

Cranston. R. I. 360 

San Juan, P. R. 360 

— .East Lansing. Mich. 280 

— Springfield. Mo. 368 

Laconia. N. H. 254 

Beloit. Wis. 242 

— Gainesville. Ga, 280 

Oklahoma. Okla. 360 

Minneapolis. Minn. 417 

Syracuse. N. Y. 234 

- Waco. Tex. 360 

.- Bellows Falls. Vt. 360 

Tusla. Okla. 360 

Houlton. Me. 28S 

..Xoulsville. Ky. 360 



.—Kalamazoo. Mich 283 
Burlington, Iowa 360 



WLAT Radio and Specialty 'co- 
WLAV Electric Shop 



WLAX Putnam Electrle Co. (Greencastie Community' "Broadcasting Station) 

wi r rr„i„„.„i. « »». Greencastie. Ind. 231 

wi w S lv f raIty ,T 0f »' n ™«>ta-~ Minneapolis. Minn. 360 

wmah Crosley Manufacturing Co. .-Cincinnati. Ohio 300 

W .M A 5 ? a i l0 . Supply Co.. _. Oklahoma. Okla. 360 



WMAC J. Edw. Page (Olive B. Meredith) 

WMAF Round Hills Radio Corp 

WMAH General Supply Co 

WMAJ Drovers Telegram Co 

WMAK Norton La horatorles 

WMAL Trenton Hardware Co 

WMAN First Baptist Church 

WMAP Utility Battery Service 

WMAQ Chicago Daily News.. 



Cazenovia, N. Y. 261 

Dartmouth, Mass. 360 

— Lincoln, Nebr. 254 

~ Kansas City. Mo, 275 

Lockport, N, Y. 360 

.- Trenton. N. J. 25S 

Columbus. Ohio 281 

— Easton, Pa. 241 

WMAV Alabama P^iyfechnir^tltufeTTI^ZTZZZZ Autam" a"!' 250 

wEa? Klngshlghway Presbyterian Church ZZZZZS . ffis. Mo. 280 

WMAZ Mercer University _ Macon Ga. 268 

wuu ''Commercial Appeal" (Commercial Publishing Ca> "-.'.Memphis. Tenn. 508 

WMU tw^'h" S}n P ?? nt .j C0 ;; - Cincinnati. Ohio 24« 

wSfar Doubleday-Hlll Electric Co Washington. D. C. 261 

WN An nS. St0T r ea ™"u nnsl °n. Mass. 278 

WNAD University of Oklahoma Norman. Okla. 360 

Omaha. Nebr. 242 

—Evansville. Ind. 360 



WNAL R. J. Rockwell- 

WNAM Ideal Apparatus Co 

WNAN Syracuse Radio Telephone Co 

WNAP Wittenberg College 

WNAQ Charleston Rr.dio Electric Co.. 

WNAR C. C. Rhodes. 



...Syracuse. N. Y. 288 
..Springfield. Ohio 231 
.Charleston, S. C. 368 
Butler. Mo. 231 



WNAS Texas Radio Corp & Austin TtetSJi^™IZZZZZ3AuillS,' Tex: 380 
W ^ A T. J-ennlg Jtrothers Co. (Frederick Lennlg) _ Philadelphia. P«_ 360 



WNAV Peoples Telephone & Telegraph Co . 

WNAW Peninsular Ttadio Club (Henry Kunzmann) 
WNAX Dakota Radio Apparatus Co... 



Philadelphia. Pa. 360 
Knoxville, Tenn. 238 



WNJ 

WOAA 

WOAC 

WOAD 

WOAE 

WOAF 

WOAG 

WOAH 

WOAI 

WOAJ 



...Fort Monroe. Va. 360 

-. „ „ ~ _ Yankton, S. Dak. 244 

Shotton Radio Manufacturing Co Albany N Y 360 

H T .\, W T?'!f> r I i ardy " Ardmore,' Okla! 360 

Mans Radio Co i, lma , hlo 266 



Friday Battery & Electrlo Corp. 

Midland College 

Tyler Commercial College 



...Sigoumey, Iowa 360 

—.Fremont, Nebr. 360 

—Tyler, Tex. 360 



Apollo Theater (Belvldere Amusement Co.) Belvldere II 224 

Palmetto Radio Corp Charleston, s' C. 360 

Southern Equipment Co San Antonio. Tex. 385 

, ™^P S E ^ ec, ^S cal Ca " Parsons. Kans. 258 

W ,2 A h Wllllan > E - Woods— Webster Groves, Mo. 228 

WO AN Vaughn Conservatory of Music (James D. Vaughn) 

u/n-An t j. w„ „ Lawrenceburg. Tenn. 360 

W /X.2 Ly™* " Mf e- Co _ Mlshawaka. Ind. 360 

X,2 AP . K alamazoo College -Kalamazoo. Mich. 240 

■V!5 A S Portsmouth Klwanls Club— Portsmouth, Va. 360 

W ,2.5 £ enry P - Lundskow.- Kenosha. Wis. 229 

W ,2 A T, S 05 " 1 M - Hamp Wilmington, DeL 360 

WOAV Pennsylvania National Guard. 2d Battalion, 112th Infantry 



WOAW Woodmen of the World. - 

WOAX Franklyn J. Wolff 

WOC Palmer School of Chiropractic. 

Iowa State College _ 

Pine Bluff Co 

John Wana maker _ 

Western Radio Co 

L. Bamberger & Co... 



Erie. Pa. 242 

Omaha, Nebr. 526 

— _ Trenton. N. J. 240 

Davenport. Iowa 484 

— - Ames. Iowa 360 

..Pine Bluff. Ark. 360 



WOI 
WOK 
WOO 
WOQ 
WOR 
WOS 

WPAB Pennsylvania State Collego __ State College'. Pa,' 283 

WPAC Donaldson Radio Co —Okmulgee. Okla. 368 

WPAD W. A. Wleboldt & Co Chicago. III. 360 

WPAH Wisconsin Department of Markets _ Waupaca, Wis. 360 



Missouri State Marketing Bureau.. 



Philadelphia. Pa. 509 

Kansas City, Mo. 360 

Newark. N. J. 405 

Jefferson City. Mo. 441 



New Haven. Conn. 268 



WPAJ Dnollttle Radio Corp 

WPAK North Dakota Agricultural College Agricultural College, N. Dak! 360 

WPAL Superior Radio & Telep. Equipment Co Columbus, Ohio 286 

WPAM Auerbach & Guettel _ 

WPAP Theodore D. Phillips „ _ _ 

WPAQ General Sales & Engineering Co.... 

WPAR Ward Battery & Radio Co 

WPAT St. Patricks Cathedral— _ __ 

WPAU Concordia College 

WPAZ John R. Koch (Dr.) _ 

WPG Nusawg Poultry Farm „ „ New Lebanon. Ohio 234 

WOAA Horace A. Beale. Jr.— ,_ Jarkersburg, Pa. 360 

WQAC E. B. Glsh Amarillo, Tex. 360 

WOAD Whltall Electric Co Waterburv. Conn. 242 

WQAE Moore Radio News Station (Hdmund B. Moore) Springfield. Vt. 275 



— Topeka, Kans. 360 

Winchester, Ky. 360 

Frostburg. Md. 360 

Beloit, Kans. 360 

El Paso. Tox. 360 

Moorhead, Minn. 380 

-Charleston, W. Va. 273 



46 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



It 

Covers 
The Field! 



Over three hundred pages of 
fully illustrated instructions 
on how to build and operate 
sets! Truly a treasure trove 
for the home radio experi- 
menter! 

Written by experts, dia- 
grammed by experts, tested 
and proved by experts. And 
all so simple and clear that 
the beginner can understand. 

All kinds of circuits, with in- 
structions on how to make 
them and amplify them. 
Readers' circuits on which 
they have made distance rec- 
ords. 

Long Distance crystal sets. 

How to hook 'em up. How 

to make the aerials do their 
darndest. 

How to make battery charg- 
ers. How to make transform- 
ers, coils, condensers, vario- 
couplers, loading coils, dry-cell 
circuits, audio-frequency amp- 
lifiers, one-tube loop aerial 
sets, two-circuit crystal de- 
tectors. 

Ten issues of RADIO AGE, 
"The Magazine of the Hour," 
the "Old Reliable" guide. 

While They Last 

In One Volume — Cloth Bound — 
with one year's subscrip- 
tion to Radio Age! 

All for $3.50 Postpaid 

Send money order or check 
now. 

RADIO AGE, Inc. 

500 North Dearborn Street 
CHICAGO 



another stage of radio frequency. About 
the only way you fellows who own big 
sets is to put a bunch of dinner plates 
on top of your cabinets, and say you had 
China on your set. Haw! Great work, 
Mr. Baumgardner. 



411 So. 18th Street, Mt. Vernon, 111. 
RADIO AGE, 

Pickups Department. 
Gentlemen: 

I am using a single-tube WD11 
hookup of the ultra audion type with 
which I have had such good results that 
I simply have to tell somebody. In ten 
days I got the following stations: KSD, 
WHB, KDKX, KDKA, WHAZ, WHAS, 
WPAD, WDAJ, WJAZ, WAAF, 
WMAQ, WDAP, WCBD, WOAW, 
WOC, WOQ, WOR, WCAP, WTAM, 
WPA, WEAF, WOS, WDAF, WCK, 
WCAH, WOAF, WCAE, WSB, WLAP, 
WLAG, WMC, WEAN, WOK, and 
WAAW. 

St. Louis is eighty miles from here, 
and Schenectady is 875, but I hear 
WGY louder than KSD. I'd like to 
know who can do that with one WD11 
tube. 

I can get any of the above stations any 
time they are transmitting, and can 
tune up as high as 600 meters. 

Guess that list ought to hold you for 
a while, so that will be all for this time. 
Yours very truly, 

DUANE ROSSELOT. 

Duane is another runner-up in the 
list of high batting averages this month. 
We are sure that many of the other fans 
will start to look for the places where 
losses occur in their sets which prevent 
them from duplicating this performance. 



In a recent letter, George Rallison en- 
closed the following list of stations heard 
with one tube: WTAM, WJAZ, WHAS, 
WLAP, WOC, WAAW, WFAA, WDAF, 
WHB, WBAP, CKCK, CFAC, CFCN, 
CHCD, KFAF, KFEL, KLZ, KDZE, 
KGW, KFEC, KGG, KFAE, KZN, 
KDYL. 

Most of these stations are over 1,000 
miles distant, with two of them over 
two thousand miles! 

Mr. Rallison is located at 418 West 
Elm Street, Hanford, Calif. When one 
considers that it is necessary to work 
over the tall Rockies to get these sta- 
tions, it makes Mr. Rallison's list a feat 
of unusual merit. 



Norwood P. O., Cincinnati, Ohio. 
RADIO AGE, 

Pickups Department. 
Gentlemen: 

I am not a subscriber to RADIO AGE, 
but I buy it at the news-stands and read 
the Pickups column in every issue. 
This is my pickup for November 23, 
1923, using one U V 200 tube, 22 1-2 
volts B battery in a Flewelling hookup, 
with antenna only: 

WOR, WDAR, WJAR, WOO, WIP, 
WGY, WWJ, WCAE, WEAF, WHAS, 
WSB, WOAI, WBAP, WFAA, WOS, 
WJAX, WJAX, WMAD, KYW, WLAG, 
WDAF, WHB, KHJ, and on the twenty- 
fifth of November I added to this list 
the following: KHJ, KFI, KLZ, KWH 
and CKCK. 

Tell the rest of the RADIO AGE 
family of Pickup readers to compare 
their lists with this one. I modestly 



acclaim it as a pretty good accumula- 
tion of DX stations. 

Very truly yours, 

S. MOESCHL. 

Listen fellows — ! You don't have to 
be a subscriber to be a pickup fan. If 
you are a reader of RADIO AGE, and 
have a list that you think is worthy of 
consideration among the rest of the 
Pickup fans, let's have it. 

If you'll allow us to comment on your 
work, Mr. Moeschl, we would add to 
your last sentence that that sure is some 
acceleration with a circuit difficult to 
manage. 



Next we have a letter from one of our 
Monon, Indiana, brothers: 
RADIO AGE, 

Pickups Department. 
Gentlemen: 

After seeing several pickup records 
published in your magazine, I have 
decided to send in a list of stations tuned 
in on a loud speaker with detector and 
two stages of audio frequency amplifi- 
cation and plate voltage of 67 volts. 

KSD, St. Louis; WHB, Kansas City; 
WDAF, Kansas City; WCBD, Zion; 
WSB, Atlanta; WMC, Memphis; WGR, 
Buffalo; KHJ, Los Angeles; WOAI, 
San Antonio; WOC, Davenport; KDKA, 
Pittsburgh; WCAP, Washington, D. C; 
WOS, Jefferson City; WOR, Newark; 
WOQ, Kansas City; WHAS, Louisville; 
WPAD, Chicago; WBAK, Harrisburg, 
Pa.; WBAA, Lafayette, Ind.; KOP, 
Detroit; KYW, Chicago; WJAZ, 
Chicago; WMAQ, Chicago; WFAA, 
Dallas; WOAW, Omaha; WEAF, New 
York City; WGY, Schenectady; KPO, 
San Francisco; WLAG, Minneapolis; 
WWJ, Detroit; WCAE, Pittsburgh; 
WBAP, Fort Worth; WLW, Cincinnati; 
WTAM, Cleveland; WTAS, Elgin, 111.; 
WDAP, Chicago; WAAP, Wichita, Kan.; 
WHAZ, Troy, N. Y.; WSAI, Cincinnati; 
PWX, Havana. 

My outfit is home assembled using 
nothing but the best parts throughout. 
I also wish to add that these stations are 
not freak pickups but stations that I 
can tune in and hear regularly. 
Yours very respectfully, 

LESLIE E. THOMAS. 

This is probably not a record break- 
ing list of stations received, but is a 
typical example of what a fellow can do 
with a set that is intelligently constructed 
and wisely operated. FB, Mr. Thomas. 



To conclude the Pickups section for 
this month, we publish this letter partic- 
ularly characteristic concerning the Rein- 
artz, The Mighty: 
RADIO AGE, 

Chicago, 111. 
Gentlemen: 

In your columns some months ago you 
published a letter of mine under "Stations 
I have heard" and at that time I was 
very enthusiastic over the Reinartz 
circuit, and still am. I have seen some 
very misleading reports concerning this 
circuit, and I really believe that such 
glowing reports come from some action 
in the set that even the maker does not 
understand. There are a million little 
things that are hardly noticeable that 
will make one set from 50 to 100 per cent 
better than one just like it, to all appear- 
ances. I believe about the best way to 
make enemies for any circuit is to boost 
it sky high and have a few disappoint- 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



47 



Complete Corrected List of U. S. and Canadian 

Broadcasting Stations 



WQAF 

WQAH 

WQAL 

vVQAM 

WQAN 

WQAO 

WQAQ 

WQAS 

WQAV 

WQAW 

WQAX 

WRAA 

WRAD 

WRAF 

WRAH 

WRAL 

WRAM 

WRAN 

WRAO 

WRAV 

WRAW 

WRAX 

WRAY 

WRAZ 

WRC 

WRK 

WRL 

WRM 

WRR 

WRW 

WSAB 
WSAC 

W8AD 
WSAG 
W8AH 
WSAI 
WSAJ 
WSAL 
W8AN 



_ _ Sandusky. Ohio 240 

Brock -Anderson Electrical Engineering Co Lexington, Ky. 254 

Coles County Telep. and Teleg. Co Mattoon, 111. 258 

Electrical Equipment Co. Miami, Fla. 360 

ScrantoD Times. Scranton, Pa, 280 

Calvary Baptist Church. New Tork. N. Y. 360 



Sandusky Register 



Abilene Daily Reporter (West Texas Radio Co.) Abilene, Tex. 360 

Prince-Walter Co - Lowell, Mass. 266 

Huntington & Guerry (Inc.) — --Greenville. S. C. 258 



Catholic University.. 
Radio Equipment Co 
Rice Institute. 



-Washington, D. C. 236 

Peoria, 111. 360 

Houston, Tex. 360 



Taylor Radio Shop (G. L. Taylor) Marlon, Kans. 248 

The Radio Club (Ino) Xaporte, Ind. 224 

Stanley N. Read. ^ Providence, R. I. 23" 



Northern States Power Co. 

Lombard College 

Black Hawk Electrical Co. 

Radio Service Co. 

Antloch College. — 



St. Croix Falls, Wis. 248 

Galesburg, 111. 244 

Waterloo, Iowa 236 

St. Louis, Mo. 360 

-Yellow Springs, Ohio 360 



Avenue Radio Shop (Horace D. Good) _ Reading, Pa. 238 

Flaxon"8 Oarage Gloucester City. N. J. 268 

Radio Sales Corp. Scranton, Pa. 280 

Radio Shop of Newark (Herman Lublnsky) _ Newark, N. J. 233 

Radio Corporation of America Washington, D. C. 469 

Doron Bros. Electric Co. _ Hamilton, Ohio 360 

Union College. Schenectady, N. Y. 360 

University of Illinois. Urbana. IlL 360 

City of Dallas (police and Are signal department) Dallas, Tex. 360 

Tarrytown Radio Research Laboratory (Koenlg Bros.) 

Tarrytown, N. Y. 273 

Southeast Missouri State Teachers College. Cape Girardeau, Mo. 360 

Clerason Agricultural College Clemson College, S. C. 360 

3. A, Foster Co. _ Providence. R. I. 261 

City of St. Petersburg (Loren V. Davis) St. Petersburg. Fla. 244 

A. J. Leonard, Jr. — Chicago, 111. 248 

United States Playing Cards Co._ : Cincinnati. Ohio 309 

Orove City College. _. Grove City. Pa. 360 

Franklin Electrio Co. Brookvllle, Ind. 246 



AUentown Radio Club.. 



...Allentown, Pa. 229 



WSAP 

WSAR 

WSAT 

WSAW 

WSAX 

WSAY 

WSAZ 

WSB 

WSL 

WSY 

WTAB 

WTAC 

WTAD 

WTAF 

WTAG 

WTAH 

WTAJ 

WTAL 

WTAM 

WTAN 

WTAP 

WTAQ 

WTAR 

WTAS 

WTAT 

WTAU 

WTAW 

WTAX 

WTAY 

WTAZ 

VVTG 

WWAB 

WWAC 

WWAO 

WWAE 

WWAF 

WWAO 

WWI 

WWJ 

WWL 



Seventh Day Adventlst Church. 

Doughty & Welch Electrical Co _ 

Donohoo-Ware Hardware C« 

John J. Long, jr. _ 

Chicago Radio Laboratory- 



.New York. N. Y. 860 

Jail River. Mass. 254 

Plalnvlew, Tex. 26$ 

Canandalgua, N. Y. 



273 

Chicago. 111. 261! 

Irving Austin (Port Chester Chamber «f Commerce) Port Chester. N. Y. 233 

Chas Electric Shop .Pomeroy. Ohio 258 

Atlanta Journal Atlanta. Ga. 429 

J. & M. Electric Co _.. Utlea. N. Y. 278 

Alabama Power Co. Birmingham, Ala. 86© 



Fall River Dally Herald Publishing Ct 

Penn Traffic Co. 



Fall River. Mass. 248 
. Johnstown, Pa. 860 



Robert E. Compten and First Presbyterian Churoh_ -.Carthage. IU. 228 

Louis J. Gallo New Orleans. La. 242 

Kern Music Co Providence. R. I. 258 

Carmen Ferro Belvldere. nL 236 



The Radio Shop _ 

Toledo Radio & Electric Co. 

Wlllard Storage Battery C». 

Orndorff Radio Shop _ 

Cambridge Radio & Electric C«_ 

S. H. Van Gorden & San. 

Reliance Electric Co. 

Charles E. Erbsteln 



Edison Electric Illuminating C» 

Ruegg Battery & Electrio C« .. 



-Portland. Me. 238 

.Toledo, Ohio 252 

Cleveland. ObU 396 

.Mattoon, I1L 240 

Cambridge, IU. 242 

Osseo, Wis. 226 

.Norfolk. Va. 280 

...Elgin, IU. 276 



..Boston, Mass. (portable) 244 
..Tecumseh, Nebr. 360 



Agricultural & Mechanical CoUege of Texas CeUege Station, Tex. 280 

Williams Hardware Co Streator, IU, 23! 



Iodar-Oak Leaves Broadcasting Station... 
Thomas J. McGulre.. 



Kansas State Agricultural College. 

Hoenlg, Swern & Co. (John Rasmussen) 

Sanger Bros 

Wright & Wright (Inc.) 

Alamo Dance Hall, L. 3. Crowley 

Galvin Radio Supply Co. 

Michigan College of Mines 

Ford Motor Co... 



Detrolt News (Evening News Asm.) 

Loyola University 



Oak Park, IU. 226 

—Lambertvllle. N. 3. 283 

.Manhattan, Kans. 48E 

.Trenton. N. J. 226 

Waco, Tex. 866 

.Philadelphia, Pa. 361 

— : JoUet. IU. 227 

Camden. N. J. 2Sf 

.Houghton. Mlcb,.._24f 

— .Dearborn. Mien. 27J 

Detroit. Mich. 517 

-New Orleans, La. 286 



Canadian Stations 



CFAC 

CFCA 

CFCF 

CFCH 

CFCI 

CFCJ 

CFCK 

CFCL 

CFCN 

CFCO 

CFCW 

CFQC 

CFUC 

CHCB 

CHCD 

CHCE 



Western Radio Co., Ltd., 

Toronto Star - 

Marconi Co. _ 

Abitlbl Power & Paper Co. Ltd. 



Calgary, Alta. 430 

Toronto. Ont. 400 

Montreal. P. Q. 440 

-Iroquois FaUs, Ont. 400 

Vancouver. B. C. 410 

Quebec, P. Q. 410 

..Edmonton, Alta 4 1 



W. W. Grant Radio, Ltd.- 



.Victoria. B. C. 400 

Calgary, Alta 440 

Bellevue, P. Q. 450 

London, Ont. 420 

Saskatoon, Sask. 400 

Montreal. P. Q. 400 

-Calgary Alta. 



..Quebec, P. Q. 



410 
410 



..Victoria. B. C. 400 



CHCL 

CHYC 

CJCA 

CJCD 

CJCE 

CJCI 

CJCN 

CJCX 

CJGC 

CJSC 

CKAC 

CKCD 

CKCE 

CKCK 

CKOC 

CKY 



Canadian Northern Else.- 

Edmonton Journal, Ltd. 

T. Eaton Co 

Vancouver Sun _ 

McLean, Holt & Co., Ltd.- 
Simmons, Agnew & Co _ 



..Vancouver, 
Montreal, 



B. C. 440 
P. Q. 410 



...Edmonton, Alta. 450 

..Toronto. Ont. 416 

420 

400 



London Free Press... 
Evening Telegram- 
La Presse.. 



Vancouver Dally Province. 

Can. Ind. Telephone Cs. 

Leader Publishing Co 

Wentworth Radio Supply Co.. 



-Vancouver, B. C. 
-St. John, N. B. 

Toronto, Ont 410 

._ Olds. Alta. 400 

London. Ont. 430 

.Toronto. Ont. 430 

—Montreal. P. Q. 430 

-Vancouver. B. C. 410 

-Toronto. Ont. 450 



Regina. Sask. 420 

Hamilton. Ont. 410 

...Winnipeg, Manitoba 450 



ments among those who attempt to build 
them. 

I read one report, in fact, several pages 
were devoted to it in a very popular 
radio magazine telling how the set 
operated four or five speakers to their 
full capacity and that programs could 
be heard at least half a mile from their 
shop. Anything is possible in radio 
but such reports are not consistent, as 
this one set is an exception and it is 
quite doubtful if it could be duplicated. 
We have also heard of the long distance 
crystal sets, and of course there are, but 
there isn't one in 100,000 that will hear 
more than forty or fifty miles at the most. 

I believe what I have accomplished 
with the Reinartz is something that 
anyone with any knowledge of radio can 
do, and I do not doubt but that many 
would have much better success than I. 
I have added four tubes to my set and 
now have two RF detector and two 
AF. The consistent distance for this 
set on a loud speaker is from 800 to 
1,000 miles, so for anyone who is centrally 
located he can feel reasonably sure that 
he will be able to get anything from the 
class B stations on his loud speaker. 
Such stations as WGR, KDKA, WJAZ, 
WBY, WOAW, WLW, WPAH, WOS, 
WDAP, we heard night after night 
regardless of weather conditions and 
these stations come in with about half 
the capacity volume of the set, taking 
the volume with which the local station 
WLAG comes on. 

The set contrary to many reports is 
quite selective, as I have received a 
majority of the above stations through 
our local stations WLAG, WBAH, 
KFEX and WCAS, without interfer- 



After adding the RF I found that the 
volume of the distance stations were 
increased approximately twice, and I 
also found that there was a great deal 
of howling, but am glad to state that this 
is not permanent as with a little practice 
one is able to tune in with very little if 
any noise, but it takes some very fine 
manipulation to tune in without any 
noise, such as howling and whistling. 
I have two of the Day-Fan RF trans- 
formers and after I have tuned in on 
one distant station can get several 
different ones merely by adjusting the 
transformers. 

I had some little trouble in installing 
the RF but after making two or three 
minor changes the set worked wonder- 
fully well. In the Reinartz circuit the 
positive A and negative B are grounded, 



but when adding radio frequency this 
ground connection is not used. A 
potentiometer is put across the positive 
of the A to negative of the A battery and 
the negative of the B battery is connected 
to the positive of the A battery as before. 
Then the potentiometer is grounded to 
the condenser in the grid circuit, this 
being an 11-plate in my set. The 
filament connections of the two RF 
transformers are connected and then 
this connection is extended to the center 
or ground connection of the potentio- 
meter, and a .002 condenser is shunted 
across the negative A battery connection 
of the potentiometer to the wire making 
the connection of the transformers to 
the potentiometer. 

Yours very truly, 

G. F. McCULLOUGH. 




When You Build Your Radio Set 

USE THE 

NEW 6 to 1 RATIO 
National Audio Frequency Transformer 



-v. 

Tested 
Radio 



and Approved 
Age Institute 



The new 6 to 1 Ratio National Is de- 
signed for use on the first stage of 
amplification. Its greater ratio means 
greater volume. All the excellent tone 
quality that characterizes the 3 1-2 to 
1 ratio has been fully retained. Min- 
imum distortion— sturdy construction — 
scientifically perfect — highly nickel 
finished. Jobbers and dealers write for 
sales proposition. 



Pri 



e— 3)4 tot 
Ratio 
Postpaid 



Price— 6 to I 

Ratio 

Postpaid 

$4 50 

National Transformer Manufacturing Co. 

154 Whiting Street Dept. 116 Chicago 



$4 



00 



48 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



ERLA BLUE PRINTS 

Erla Receivers out-distance other sets with anfalmost 
unbelievable volume and a naturalness that cannot be 
distinguished from the source of reception. 

This is the famous Erla Reflex Hook-up. Less than 
one year old — but has taken the entire nation by storm. 
Every listener-in raves about it and wants a set of his 
own immediately. 

So easy to construct that anyone who can handle a 
screw driver can build the set complete in a sur- 
prisingly short time — about 1 1-2 hours. Everything 
is so simple and easy. 

NO SOLDERING WHATEVER— ONLY A 
SCREW DRIVER NEEDED. 

The results from the Erla 3 tube is naturalness itself and can- 
not be improved upon. Actual size working diagrams make 
every thing simple and easy. Every piece of apparatus and 
every wire is pictured in its exact place — every article needed 
is listed on the diagrams. 

Diagrams sent same day your order is received. 
Send P. O. or Express Money Order or Bank draft 
or Bank Cashier's check. Do not send stamps or 
personal checks. 

Erla Hook-up Diagram Prices 

3 sheets for making 1 tube set 25c 
3 sheets for making 2 tube set 35c 
3 sheets for making 3 tube set 50c 



Frank D. Pearne 

Sole Distributor of Erla Diagrams for U. S. and Canada 
829 Waveland Avenue, Chicago, III. 

Dealers, Write for Quantity Prices 



We are very grateful to Mr. McCul- 
lough, 1826 Park Avenue, Minneapolis, 
Minn., for his interesting letter, and are 
glad to learn that he gets results. One 
can readily learn from his letter that 
consistent results come from patient and 
painstaking design, construction and 
operation. Remember, that if you make 
thirty little improvements on a set and 
each one does not have the property of 
being noticeable in the phones you feel 
that not much has been accomplished; 
on the other hand, if the whole thirty 
changes and improvements could be 
made at once, the increase in efficiency 
would immediately be noticed. Just 
keep Mr. McCullough's words in mind 
when working out any new change. 



We regret very much the inability to 
publish all the letters from the many- 
fans who sent in lists in response to our 
call. However, we wish to acknowledge 
letters from Messrs. H. Q. Ten Eyck, of 
215 W. Goepp Street, Bethlehem, Pa., 
who says he has a circuit of unusual 
merit which can be had merely for the 
writing; James E. Chandler, of Belvi- 
dere, 111.; A. Des Rosius, of Windsor, 
Ontario, Canada; and from W. O. Halter 
of 357 South La Salle Street, Aurora, 
111., and others. 

Well, fellows, we'll sign off in code 
this time jes' like a regular amateur 
station: 

"Gess nm nw so best 73's Hppy es 
Prosperus Nw Yr., SK" 

RADIO AGE PICKUPS AND 
HOOKUPS DEPT. 



Kable Band 

Many listeners of that sterling station, 
WOC, Davenport, Iowa, were pleased 
on the night of November 30 to hear a 
radio concert given by the Kable Brothers 
Company band. Kable Brothers print 
magazines at Mount Morris, 111., but 
they mix play with their work and they 
have organized a musical organization 
of exceptional merit. RADIO AGE 
listened in and can commend with 
authority the performance at Davenport. 
Furthermore, it is a pleasure to register 
approval since Kable Brothers Company 
is our printer. 

Miss Anna Leeb, assistant business 
manager of RADIO AGE, charmed the 
audience of Station WJAZ a few nights 
later by singing several songs that 
proved her to be a vocalist of accomplish- 
ment. Miss Leeb has a soprano voice, 
well suited to such songs as "I Love You 
Truly" and "Mighty Lak a Rose," both 
of which she sang, with the result that 
there were numerous telephone requests 
for encores. 

It was the privilege of the editor of 
RADIO AGE on one of the Wednesday 
nights when the Zenith- Edge water Beach 
Station talks with Explorer MacMillan 
to talk to Dr. MacMillan up there near 
the North Pole, and tell him how interest- 
ed all radio fans were in the success of 
his adventure. 

Yes, the RADIO AGE family are 
bugs, like the rest of you. 



Best Hook-up Book 
Ever Printed 

NO BUILDER of home-made receivers, or home-made parts, should spend time 
and money on any circuit without first getting this standard, comprehensive and 
up-to-date guide. It should be on every home work bench. It shows you how to 
start right and leads you to successful completion of your work. 

All the popular standard hook-ups are described. Throughout the book are 
numerous full page drawings showing all the parts and wires as they should be as- 
sembled. You cannot go wrong following these picture diagrams. Even the most 
complicated circuits are simplified. Wiring diagrams are added for those who need 
or want them. 



Simple Crystal Set 

Long Distance Crystal Set 

Your First Tube Set 

Kopprasch Circuit 

Erla Reflex 

Kaufman 

Grimes Inverse Duplex 

Two Stage Amplifier 

Junior Heterodyne 

One Tube with Loop Aerial 

Wave Trap, Filter, Eliminator 

Loading Coils 

Transformers 

Battery Charger 



Reinartz 

Hopwood 

Haynes 

Cockaday 

Neutrodyne 

Three-circuit Tuner 

Super-Heterodyne 

Simple Radio Frequency 

Ultra Audion 

Rosenbloom 

Push-Pull Amplifier 

Portable Reinartz 

Wave-Meters 

Two-Circuit Crystal 



That is an imposing array of material but it is only a part. There are many 
pages of information on antennae, tuning, soldering, diagram symbols, etc. Com- 
plete instructions on how to learn the code. All written and illustrated by experts. 

On The Press Now! 

Big Sales Assured 

Order Now For First Delivery 

Send only $1 as payment in full to address below. Don't blame us if you are 
behind time. Send money order, check, currency. If by check add 5 cents for ex- 
change. 

Nothing else like it, 

Nothing else as good as 

THE RADIO AGE ANNUAL 

For 1924 

Make all remittances to RADIO AGE, Inc., 500 North Dearborn Street, 
Chicago, 111. 



Radio" dealers, news-dealers and booksellers, write for prices 




V--- - — ' 



BB 





THE AMERICAN RADIO RELAY LEAGUE 

HARTFCRO. CON* 







RADIOGRAM 


- 


t- . 


— 


fc. 


"iir"" 







E==9 



Inside the Arctic Circle, nine degrees 
from the North Pole, a little 89-foot schooner is 
frozen fast in the ice of Smith Sound. Aboard 
this schooner a group of brave men are enduring, 
as best they can, the desperate cold of the Arctic — 
cold that often drops to 60 degrees below zero. 
Human atoms in a boundless field of ice! 

Cold is hard to endure, but far more terrible is the 
Arctic solitude — unbelievably oppressive. Radio, at 
length, has broken this spell forever! 

Concerts from Honolulu! 

Daily, by means of powerful sending and receiv- 
ing apparatus, the crew of the "Bowdoin" are in 
communication with relatives and friends in the 
far-off States. Daily they listen to concerts as far 
away as Chicago, Dallas, and Honolulu ! 

When the sanity, the very lives of one's shipmates 
may depend upon contact with the outside world, 
none but the best is good enough. 

Dr. MacMillan 9 s Choice — the Zenith 

Out of all the radio sets on the market, Dr. 
MacMillan selected the Zenith exclusively — because 
of its flawless construction, its unusual selectivity > 
its dependability and its tremendous reach. 

Already his operator, on board the "Bowdoin" in 
Northern Greenland, has tuned in several hundred 
stations. You along the Atlantic who brag a little 
when you tune in Catalina Island^ what would you 
say if you tuned in Hawaii from the Arctic Circle? 

The set that Dr. MacMillan has is a standard 
Zenith receiving set. And you can do all that 
MacMillan does, and more, with either of the two 
new models shown at the right. Their moderate 
price brings them easily within i 
your reach. Write today for \ 
full particulars. 

Zenith 
Radio Corporation 

Dept. Y 
McCormick Building 
"AGO 



Model 4R— The new Zenith 4R "Long-Distance" 
Receiver-Amplifier comprises a complete three- 
circuit regenerative receiver of the feed-back type. 
1 It employs the Zenith regenerative circuit in 
combination with an audion detector and three- 
stage audio-frequency amplifier, all in one cabinet. 
Because of the unique Zenith "selector," unusual 
j selectivity is accomplished without complication of 
' adjustment. 

The Zenith 4R may be connected directly to any 

loud-speaker without the use of other amplification 

for full phonograph volume, and reception may be 

| satisfactorily accomplished over distances 

J of more than 2,000 miles 



$85 





CHIC^ 




Model 3R— The new Zenith 3R "Long-Distance" 
Receiver-Amplifier combines a specially designed 
distortionless three-stage amplifier with the super- 
efficient Zenith three-circuit regenerative tuner. 

Fine vernier adjustments — in connection with the 
unique Zenith aperiodic or non-resonant "selector" 
primary circuit — make possible extreme selectivity. 

2,000 to 3,000 Miles with Any Loud-Speaker 

The new Zenith 3R has broken all records, even 
those set by its famous predecessors of the Zenith line. 
Satisfactory reception over distances of 2,000 to 3,000 
miles, and over, is readily accomplished in full 
volume, using any ordinary loud-speaker. No 
special skill is required. 

The Zenith is the only set built which is capable of 
being used with all present-day tubes as well as 
with any tubes that may be brought out in the future. 
The Model 3R is compact, graceful in line, and 
built in a highly finished mahogany cabinet 



$160 



! ZENITH RADIO CORPORATION, Dept. Y 
I 332 South Michigan Avenue, Chicago, Illinois 

I Gentlemen:— ... _ ,. 

Please send me illustrated literature on Zenith Radio. 



I 



Name . 



I Address. 



The Magazine of the Hour 




^Ste - 



-*r 



IN THIS NUMBER. 



Another device for tun- 
ing out interference. 



How the antenna actual- 
ly functions. 



low to make a one-tube 
Heterodyne. 



evelopment of your 
Reinartz Circuit. 



interesting new tun- 
ing unit. 



Complete corrected list 
of Broadcasting sta- 
tions. 

More good hookups. 



■,/ 



4 






■~<s r 







gjp^ 



1924 





j?* 








:fx 



^^^_.^__. 



; 



Your Radio Problems Solved 
for 30 Cents in Stamps 

IF YOU are constructing a receiving set, a battery charger, a loading coil, a con- 
denser, or a transformer and you need help in the way of clear diagrams and full 
detailed descriptions of that very thing you may have it by return mail. 

We have laid aside a limited number of back numbers of Radio Age for you. Be- 
low we are listing the hook-ups and circuit diagrams to be found in these magazines. 
Select the ones you want, enclose 30 cents in stamps for each one desired. 

We advise immediate attention to this as the stock of back numbers is diminish- 
ing rapidly. 



May, 1922 

— How to make a simple Crystal Set for $6. 

June, 1922 

— How to make a Receiving Transformer. 
— Aerials under ground and under water. 
— Electric light wires as auxiliary to radio. 

September, 1922 

— How to construct the Reinarti Receiver. 
— Federal Act regulating radio. 

October, 1922 

— How to make a Tube Unit for $23 to $37. 
— How to make an Audio Frequency Amplifying Trans- 
former. 

November, 1922 

— Photo-electrio Detector Tabes. 

— Design of a portable short-wave radio wavemeter. 



December, 1922 

— Supply exhausted. 

January, 1923 

— How to make a sharp-tuning Crystal Detector. 
— Fixed condensers in home-made receiving sets. 
— Description of loading coil for simple sets. 

April, 1923 

— The Kopprasch eircult. 

— How to make a one-tube loop aerial set. 

— A two-oircuit Crystal Set. 

May, 1923 

— How to make the Erla single-tube reflex receiver 
— How to make a portable Reinarts set for summer use. 



June, 1923 

— How to build the new Kaufman receiver. 
— What about your antenna? 

July, 1923 

— The Grimes inverse duplex system. 
— How to read and follow symbols. 
— Proper antenna for tuning. 

August, 1923 

— Construction of the Cookaday four-oircuit tuner. 

— An efficient two-stage amplifier. 
— A simple buzzer transmitting set. 

September, 1923 

— How to load your set to receive new wave lengths. 
— Simple Radio Frequency Receiver. 

October, 1923 

— The Four-Tube Neutrodyne. 
— Tour First Tube 8et. 

November, 1923 

— The Super-Heterodyne. 
— A Three-Circuit Tuner. 
— How to Learn Code. 

December, 1923 

— Building the Haynes Receiver. 

— Combined Amplifier and Loud Speaker. 

— A selactive Crystal Receiver. 

January, 1924 

— Tuning Out Interference — Wave Traps — Elimina- 
tors — Filters. 

The article which was favored with the grateful interest of the 
radio public after its announcement by Station WJAZ. 

— A Junior Super- Heterodyne. 
— Push- Pull Amplifier. 
— Rosenbloom Circuit. 



RADIO AGE, Inc. 



500-510 North Dearborn Strut, 



CHICAGO, ILL. 



3C 



3T 



^T 



5S 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 




Inside the Arctic Circle, nine degrees 
from the North Pole, a little 89-foot schooner is 
frozen fast in the ice of Smith Sound. Aboard 
this schooner a group of brave men are enduring, 
as best they can, the desperate cold of the Arctic — 
cold that often drops to 60 degrees below zero. 
Human atoms in a boundless field of ice! 

Cold is hard to endure, but far more terrible is the 
Arctic solitude — unbelievably oppressive. Radio, at 
length, has broken this spell forever! 

Concerts from Honolulu! 

Daily, by means of powerful sending and receiv- 
ing apparatus, the crew of the "Bowdoin" are in 
communication with relatives and friends in the 
far-off States. Daily they listen to concerts as far 
away as Chicago, Dallas, and Honolulu ! 

When the sanity, the very lives of one's shipmates 
may depend upon contact with the outside world, 
none but the best is good enough. 

Dr. MacMillan 9 s Choice— the Zenith 

Out of all the radio sets on the market, Dr. 
MacMillan selected the Zenith exclusively— because 
of its flawless construction, its unusual selectivity, 
its dependability and its tremendous reach. 

Already his operator, on board the "Bowdoin" in 
Northern Greenland, has tuned in several hundred 
stations. You along the Atlantic who brag a little 
when you tune in Catalina Island — what would you 
say if you tuned in Hawaii from the Arctic Circle? 

The set that Dr. MacMillan has is a standard 
Zenith receiving set. And you can do all that 
MacMillan does, and more, with either of the two 
new models shown at the right. Their moderate 
price brings them easily within 
your reach. Write today for 
full particulars. 

Zenith 
Radio Corporation 



Model 4R— The new Zenith 4R "Long-Distance" 

I Receiver-Amplifier comprises a complete three- 
I circuit regenerative receiver of the feed-back type. 
~i It employs the Zenith regenerative circuit in 
I combination with an auction detector and three- 
I stage audio-frequency amplifier, all in one cabinet. 
Because of the unique Zenith "selector," unusual 
I selectivity is accomplished without complication of 
j adjustment. 

The Zenith 4R may be connected directly to any 

loud-speaker without the use of other amplification 

I for full phonograph volume, and reception may be 

satisfactorily accomplished over distances (fa q C 

of more than 2,000 miles vpOO 




Dept. F, McCormick Building 
CHICAGO 



r*s* 




Model 3R— The new Zenith 3R "Long-Distance" 
Receiver-Amplifier combines a specially designed 
distortionless three-stage amplifier with the super- 
efficient Zenith three-circuit regenerative tuner. 

Fine vernier adjustments — in connection with the 
unique Zenith aperiodic or non-resonant "selector" 
primary circuit — make possible extreme selectivity. 

2,000 to 3,000 Miles with Any Loud-Speaker 

The new Zenith 3R has broken all records, even 
those set by its famous predecessors of the Zenith line. 
Satisfactory reception over distances of 2,000 to 3,000 
miles, and over, is readily accomplished in full 
volume, using any ordinary loud-speaker. No 
special skill is required. 

The Zenith is the only set built which is capable of 
being used with all present-day tubes as well as 
with any tubes that may be brought out in the future. 
The Model 3R is compact, graceful in line, and 



$160 



built in a highly finished mahogany cabinet 

, ZENITH RADIO CORPORATION, Dept. F 
| 332 South Michigan Avenue, Chicago, Illinois 

Gentlemen: — 

Please send me illustrated literature on Zenith Radio. 



Name . 



I Address. 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



RADIO AGE 

The Magazine of the Hour 

(Established March, 1922) 



Volume 3 



FEBRUARY, 1924 



Number 2 



CONTENTS 

Page 

The Reinartz Audio Regenerator 5 

By Felix Anderson. 

A One Tube Heterodyne. 7 

By John B. Rathbun. 

Analogy of the Receiving Antenna 9 

By Frank D. Pearne. 

Interference Rejectors 11 

By Felix Anderson. 

A New Tuning Unit 15 

By Frank D. Pearne. 

How to Avoid Interference -.21 

By J. V.L. Hogan. 

The Superdyne Receiver ...25 

How to Make a Battery Charger 27 

What the Broadcasters Are Doing 29 

Pickups and Hookups By Readers.. ....34 

Troubleshooter 40 

Corrected List of Calls 43 

With Wave Lengths. 



Radio Age is published monthly by 
RADIO AGE, Inc. 

Publication office, Mount Morris, 111. 

Editorial and Advertising Offices, Boyce Building, 

500 N. Dearborn St., Chicago 

Frederick Smith, Editor 
Frank D. Pearne, Technical Editor 
M. B. Smith, Business Manager 
Louis L. Levy, Circulation Director 

Western Advertising Representatives 

BRUNS & MACDONALD 

First National Bank Building, Chicago 

Eastern Representatives 

E. V. HEVEY & COMPANY 

17 West 42nd Street, New York City 

Telephone, Longacre 1698 

Advertising forms close on the 15th of the month 
preceding date of issue 

Issued monthly. Vol. 3, No. 2. Subscription price $2.50 a year. 

Entered as second-class matter September IS, 1922, at the post office at Mount 

Morris, Illinois, under the Act of March 3, 1879 



Copyright, 1924, by RADIO AGE, Inc. 



70,000! 

AS THE forms for the February 
issue are about to close it 
looks as if 70,000 would be the 
minimum press run for this month. 
Dealers' orders are still coming in 
as this is written and most of them 
call for substantial increases over 
January. We are likely to need 
75,000 copies. 

One Chicago magazine shop sold 
out its RADIO AGE supply three 
times on January 7 and when our 
distributor reached the store with 
a fourth consignment of the Jan- 
uary issue, thirty customers were 
waiting for their "Magazine of the 
Hour." That little loop store sold 
900 copies in one day. 

"Sold out clean" said a telegram 
from Montreal, almost immediately 
after receiving the January issue. 
Pawtucket, Rhode Island, next came 
in with a telegram asking that their 
original order be duplicated. Long 
distance telephone calls, telegrams, 
letters and personal visits from 
dealers steamed things up until the 
business manager had to telephone 
the printing house to put the forms 
all back on the presses for a second 
run. 

We told you on this page of the 
January issue that this was distinc- 
tively a reader's magazine and we 
explained how we had attained a 
prosperous success, practically on 
circulation alone. Now we are go- 
ing to tell you what made that 
January issue sell like peanuts at 
a circus. 

It was the article on "Tuning out 
Interference." It was the best and 
most comprehensive article on the 
subject thus far published. E. F. 
McDonald, Jr., president of the 
Zenith Radio Corporation, broad- 
cast some kind words about the 
article from Zenith-Edgewater Sta- 
tion WJAZ and other stations fol- 
lowed his example. That announce- 
ment over the air introduced us to 
more than 20,000 new readers. 
Their letters have been coming in 
— and their subscriptions. We 
thank the broadcasters and the 
broadcast listeners. We promise to 
reciprocate by continuing to do our 
best to print a good radio maga- 
zine. 

—Editor, RADIO AGE 



THE 




S S 



Eveready " Three" 

4V2 volts, three distinct uses. 
Length, 4 in.; width, 1% in.; 
height, 3 in.; weight, 14 oz. 
At all reliable radio dealers. 



This "C" Battery is a Wonder Worker 



YOU can make the loud speaker respond 
with a new fullness and naturalness of 
tone. You can save money by adding months 
to the life of your "B" Batteries. These 
things you can do by using the new Eveready 
"Three" as a "C" Battery. 

You already have an "A" Battery for the 
filament and a "B" Battery for the plate. A 
"C" Battery is connected to the third element 
of your vacuum tube, the grid, affording a 
control that is marvelous in action on audio 
frequency amplifiers. 

As a "G" Battery the Eveready "Three" 
prevents distortion and excessive flow of 
current from the "B" Battery, lengthening its 
life. It is a wonder worker that saves its 
small cost many times over. Connect it in 
your audio frequency amplifier and note the 
difference. Full directions on the label and 



in "How to Get the Most Out of Your 'B' 
Battery," a booklet on "B" and "C" Batteries, 
sent free on request. 

This triplcuse battery can also be used as 
an "A" Battery in portable sets. Light and 
full of pep. Its third use is as a "B" Battery 
booster. 

Use the Eveready "Three" — a tested prod- 
uct of the world's leading electro-chemical 
battery laboratory. It serves more radio uses 
and effects more economies than any radio 
battery heretofore developed. 

If you have any battery problem, Radio 
Battery Information Headquarters will solve 
it for you. Write G. C. Furness, Manager, 
Radio Division, National Carbon Company, 
Inc., 202 Orton Street, Long Island City, 
New York. 



NATIONAL CARBON COMPANY, Inc., New York— San Francisco 

Headquarters for Radio Battery Information 
CANADIAN NATIONAL CARBON CO., Limited Factory and Offices: Toronto, Ontario 

EVEREADY 

Radio Batteries 

-they last longer 




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RADIO AGE 

"THE MAGAZINE OF THE HOUR" 



M. B. Smith 

Publisher 



A Monthly Publication 

Devoted to Practical 

Radio 



Frederick A. Smith 

Editor 



The Reinartz Audio Regenerator 



HEARKEN 'ye Reinartz followers! 
Drag out the tool kit, count over 
the radio budget, and learn how to 
make a set that will rattle the diaphragms 
of your telephone receivers. 

To make improvements and adapta- 
tions on a good circuit is always in order. 
We are, therefore, presenting to our read- 
ers several new circuits and adaptations 
of the Reinartz circuit which have 
evolved since the original presentation 
of this system in June, 1922. 

The original Reinartz circuit consists 
of a spider web coil wound in auto trans- 
former fashion, with a capacity (con- 
denser) shunted across its grid circuit 
inductance. It is a well known fact that 
an arrangement of this kind does not de- 
liver as great a voltage variation to the 
grid of the tube as would an arrangement 
comprising a large variable inductance, 
making it unnecessary to use the capacity 
for tuning purposes. 



By FELIX ANDERSON 

Technical Assistant, Radio Age 

Acting upon this principle, John Rein- 
artz, originator of the Reinartz circuit, 
and owner and operator of radio station 
1QP — evolved the circuit shown in Fig- 
ure 2. Instead of tuning the grid circuit 
with a condenser as was outlined in the 
September, 1922, issue of RADIO AGE by 
Mr. Pearne, Mr. Reinartz substitutes a 
large variable inductance to accomplish 
this purpose. 

The originator of this circuit claims it 
is so much better than the original spider 
web system, that he advises those using 
the first system to give this new permu- 
tation a trial. 

Construction 

To construct this set, it will be neces- 
sary to rewind a standard variocoupler. 
This is about the only drawback of the 
system, but it will be found that no dif- 
ficulty will be experienced by the average 
fan who has by this time become familiar 
with winding coils of all descriptions and 



sizes in the course of his radio experi- 
ments. In purchasing the variocoupler 
get one in which the tube is not more 
than three and one-half inches in diam- 
eter, and which has a rotor large enough 
to accommodate fourteen turns of No. 18 
SSC insulated wire, on each side of the 
shaft. 

The primary is wound in the following 
manner. Punch two holes in the card- 
board tubing, and start winding, using 
No. 18 SSC wire. The first ten turns are 
tapped every turn as shown in the sketch 
in Figure 1. This winding should start at 
the end opposite the rotor of the tuner. 
After the first ten turns are wound, com- 
plete the coil by winding 35 turns with- 
out taps, leaving an end sufficiently long 
for connecting purposes. 

The rotor should then be rewound as 
mentioned above, with 28 turns of the 
same size wire, placing 14 turns on each 
half of the rotor. 



T 



AERIAL 



43PIATE >OOl MF 



23PI(1T£ .CMOS' MF 



&ROOND 




AMP 



Hill 



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Bt> BAT /b-ZOi/ 8a BAT 6Jfz\/ 

Figure 2 — The wiring diagram j 'or the Reinartz Audio Regenerator. If it is found that the tube must be turned on dangerously 
high to make the set oscillate properly, a choke coil consisting of about six turns of the same size wire as is used on the tuner on a 
1-inch tube should be inserted at the point marked X. 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 




REACTANCE COJl SHOULD 
BBUJOUND /A) RZUCZSE 
DJ RECTI ON 7D COIL L 

▼" 8 BAT- 30-4FV. 

Figure 4 — Another permutation of the Reinartz set with tuned radio frequency amplification. The accompanying article give* 
the necessary constants for building this set. 



The 45th turn on the stationary coil is 
then connected to the first turn on the 
rotor as shown at "A" on the isometric 
sketch. This puts the two coils in series, 
very much like a variometer. 

Additional Apparatus 

For those who already have Reinartz 
sets, very few additional parts other than 
the variocoupler will be necessary, but 
for those constructing the first set of this 
type, we are printing a complete list of 
apparatus necessary. The parts are: 

1 43 plate vernier variable condenser. 

1 23 plate vernier variable condenser. 

2 .0025 or .003 fixed condensers. 
2 tube sockets. 

2 rheostats, resistance depending on 
type of tube used. 

1 set of phone tip jacks. 
1 dozen switchpoints. 
1 switch lever. 

1 standard 4 or 6 to 1 audio frequency 
transformer. 

5 Fahnstock binding posts. 

2 standard binding posts. 

1 7x15 inch bakelite or formula panel. 

1 variocoupler fulfilling the specifica- 
tions aforementioned. 

Bus bar, mounting board, phones, 
tubes, batteries and other customary ac- 
cessories. 

After the parts have been acquired, the 
builder should arrange them on the panel 
and mounting board as shown in the 
isometric sketch. 

If a single hole is drilled in the back of 
the cabinet, which should be of the hinged 
top type, all the battery wires may be 
run into the set through this hole and 
connected with ease to the spring type 
of binding posts as shown in the sketch. 
The antenna and ground posts are of 
more attractive design to preserve the 
general appearance of the set. 
Operation 

The set makes use of the audio re- 
generation principle, inasmuch as the 



condenser connected to the plate of the 
second tube feeds back capacitatively the 
audio currents of the second valve, very 
much in the same manner as the radio fre- 
quency is fed back to the antenna from 
the plate of the first tube. It will be 
noted that the grid condensers change 
their capacities from the usual .00025 to 
.0025 or .003 MF. This, with the open 
low voltage connection on the audio 
frequency transformer are practically the 
only departures from the usual circuits. 

Mr. Reinartz claims that this permu- 
tation is easily equal to a two stage am- 
plifier if properly constructed and intel- 
ligently operated. 

The adjustments of the 23 plate con- 
denser control the tone of the signal, and 
permits reception with 'unusual clarity. 
If, however, the condenser mentioned is 
advanced too far, the signal while ter- 
rifically amplified will contain an audible 

AEML 

NO l<b DCC 

3 inch ruse 



oscillation or tube howl. The condenser 
should be adjusted to a point where the 
circuit is so called "triggered off," an in- 
termediate point where the circuit is quiet 
and clear. The signals are as produced by 
this triggering action clear, sharp and 
clean, and without "mush." 

The set will function with practically 
any type of tube, but for the best results, 
a U V 200 should be used with about 16 or 
18 volts on the plate and coupled to the 
second tube which should be either a 
WE VT 1 or other amplifying tube by 
an Acme transformer. 

Other Improvements 

Through the Technical Office of this 
magazine, the writer notices many re- 
quests for different permutations of the 
Reinartz circuit with radio frequency 
amplification of the tuned type. Figure 
3 shows one type of circuit which is some- 
times effective in this respect. The con- 
stants of the circuit are shown on the 
diagram, and need no comment. 
(Continued on page 48) 




Figure 3. The Reinartz circuit in connection with the tuned impedance radio fre- 
quency method of low frequency amplification. This method is highly efficient in tuning 
over a broad band of waves. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



Single Detector Tube Heterodyne 

By JOHN B. RATHBUN 



FOR the experimentally inclined 
this pocket edition heterodyne re- 
ceiver will prove exceedingly inter- 
esting and instructive, and further still 
can be made the nucleus of a full fledged 
super-heterodyne set should the builder 
decide later to add the necessary stages 
of amplification. Properly constructed 
and handled, this baby of the heterodyne 
family is capable of very good results, 
particularly where there is much inter- 
ference between local broadcasting sta- 
tions. Its selectivity is one of its crown- 
ing features. 

So much has been said of late on the 
working principles of the heterodyne and 
super-heterodyne that it seems almost 
unnecessary to enter into anything more 
than a brief outline of the heterodyne 
theory at this point. The purpose of 
the unit shown here is to adjust the tun- 
ing circuit to the frequency of the in- 
coming radio impulses and then to aug- 
ment these feeble waves by super-im- 
posing other waves from a local oscillat- 
ing tube upon the tuning circuit. The 



normal oscillations in the detector- 
tuner circuit of a regenerative set, 
where (al) is the "amplitude" or inten- 
sity of the radio waves. Fig. 2 shows 
the amplitude (a2) of the waves created 
by the local oscillator tube, and by a 
suitable supply of energy to this tube 
we can make the amplitude of the 
artificial oscillations several times greater 
than the value of the incoming radio 
waves shown in Fig. 1. The separate 
local oscillator tube can be adjusted to 
give any desired wave length so that these 
oscillations are very close to the fre- 
quency of the incoming oscillations. 

In Fig. 3 we have the oscillations from 
the oscillator tube impressed on the tuner 
circuit and so that the radio waves are 
in phase or in step with the waves of the 
oscillator tube. The total wave result- 
ing from the two superimposed waves is 
shown by the heavy full curve and it will 
be seen that the amplitude of this wave 
(a3) is equal to the sum of the ampli- 
tudes (al) and (a2) and that the ampli- 
fication of the original incoming wave 



have another condition of wave summa- 
tion. In the super-heterodyne the in- 
coming radio waves from the aerial and 
the waves from the local oscillator are 
slightly "out of phase" or out of step 
in order to gain an interference which is 
commonly known as the "heterodyne 
note" or "beat note." It is by this 
method that we reduce the high frequency 
radio wave of the broadcasting station 
to a lower frequency wave. 

Let us say that our radio amplifying 
transformers are adjusted for a maxi- 
mum amplification at a frequency of 
100,000 cycles per second, but that the 
incoming radio waves from the broad- 
casting station have a frequency of 800,- 
000 cycles per second. This change of 
frequency from 800,000 to 100,000 cycles 
can be easily produced by the heterodyne 
method in which the independent local 
oscillator tube is made to impress a 
frequency of 700,000 cycles in the tun- 
ing circuit. The total or resultant fre- 
quency in this circuit is equal to the 
difference in the frequency of the radio 



j— W/i_ 




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sum of the wave amplitude or wave in- 
tensity in the circuit is then made equal 
to the sum of the radio wave intensity 
and the oscillation wave intensity. This 
in a way is quite similar to the method 
used in feed back regenerative systems 
where the plate energy is fed back in- 
ductively into the secondary tuner coil 
except that a separate tube is used for 
this purpose. In fact, every regenerative 
circuit is to a certain extent a heterodyne 
in which the detector tube at once per- 
forms the functions of detector, oscillator 
and amplifier. 

Using a separate tube as an oscillator 
is far more efficient, however, than using 
the detector tube for this purpose for 
there is no interference between the three 
functions when the separate oscillator 
tube is adjusted to the proper point for- 
maximum oscillation. The proper fila- 
ment adjustment for 
oscillations is sel- 
dom the best ad- 
justment for detec- 
tion oramplification, 
hence the single 
tube regenerative or 
"autodyne" cannot 
be expected to de- 
liver the maximum 
output when work- 
ing under all three 
principles. 

Fig. 1 shows the 



can be performed by adding another local 
wave to it. In the regenerative circuit 
or "autodyne," the detector tube sup- 
plies the wave (a2) and amplification is 
had to a lesser degree by the "feed-back 
method." In our present system with 
the separate heterodyne we can have the 
increase due to the detector tube plus 
the further increase due to the super- 
imposed waves of the oscillator so that 
the total is much greater than before. 

In all these figures we have assumed 
all of the waves were in step or in "phase," 
and that they were simple "sinusoidal" 
waves as delivered by the broadcasting 
station. This condition is best for the 
heterodyne having a single detector tube, 
but in the super-heterodyne where we 
are to reduce the effective wave length 
at the output of the detector for ampli- 
fication in the following radio stages, we 



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waves and oscillator waves, or numer- 
ically: 800,000 -700,000 =100,000 cycles 
per second in the circuit. 

Since the waves must be out of step 
at the two frequencies of 800,000 and 
700,000 cycles, the resultant wave is not 
exactly equal to the sums of the ampli- 
tudes but is somewhat less, and further- 
more, the resultant wave of 100,000 
cycles is no longer a pure sinusoidal curve 
but an irregularly shaped curve having 
several humps or peaks. In Fig. 4 we 
show the oscillator wave (b) out of phase 
with the radio wave (a) by just enough 
to produce the resultant wave (c) of 
100,000 cycles. Since the amplitude of 
the wave (c) is equal to the sums of the 
other two amplitudes at every point in 
the length of the curve, we have a badly 
distorted "harmonic" which has a longer 
wave length than either of the other 
two waves. 

When operating 
the single tube cir- 
cuit we are operating 
more nearly under 
theconditionsshown 
by Fig. 3 with all 
waves in phase or 
nearly so, but when 
we use the oscillator 
on a super-hetero- 
dyne having subse- 
quent radio fre- 
quency amplifica- 



tion at low frequencies then we 
control our oscillator tube so that the 
wave systems are out of phase as in Fig. 
4. This is the only difference between 
our present single detector tube "baby" 
and the aristocratic super-heterodyne 
with two or three bushels of tubes. By 
use of the variable condenser which con- 



RADIO AGE- "THE MAGAZINE OF THE HOUR' 




trols the oscillator tube, we can have 
the wave systems either in phase or out 
of phase at pleasure, hence we can use 
the circuit as a plain heterodyne or super- 
heterodyne at will. 

SIMPLE SINGLE TUBE CIRCUIT 

A simple single tube heterodyne can 
be made by introducing certain modi- 
fications into the common feed-back re- 
generative circuit so that the frequency 
of the plate circuit can be varied in re- 
spect to the frequency in the grid cir- 
cuit. That is, the plate current is fed 
back inductively into the grid circuit in 
the usual way but additional means of 
frequency control are introduced into 
the plate circuit. A variable inductance 
such as a variometer may be used in series 
with the plate circuit or else a "tuned 
impedance" having an inductance coil 
and variable condenser can be inserted 
into the plate circuit. The latter is 
probably the more effective and will be 
used in the circuit described. 

Fig. 5 contains the amplifier tube 
(T) with the grid condenser (Kl) and 



grid leak (G). The tuning unit for wave 
length adjustment consists of a fixed 



coupler having the primary coil (P) and 
the secondary coil (S). The secondary 
coil is tuned by the variable condenser 
(CI) in the usual manner. The filament 
battery is at (A) with the rheostat (R). 
So far, the circuit is that of any simple 
tube circuit. 

Plate current from the battery (B) 
{Continued on pa^e 38.) 







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RADIO AGE— "THE MAGAZINE OF THE HOUR" 



Analogy of the Receiving Antenna 

By FRANK D. PEARNE 



JUST how the signals from a broad- 
casting station are received upon the 
aerial is somewhat of a mystery to 
the average radio enthusiast. He knows 
that the aerial is a very essential part of 
his receiving set and that almost any 
conductor strung across the roof, or be- 
tween any high supports, will bring in the 
signals. 

He will study carefully the different 
types of receiving sets to make sure that 
he understands which is the best for his 
particular needs and after it is con- 
structed, he stretches a wire, or wires, 
across the roof with hardly any thought 
other than that of making it as high and 
as long as possible. 

If he really understood just how the 
energy is received and just what action 
takes place in this very important part of 
his apparatus, he might be able to greatly 
increase the tone and quality of his re- 
ception. However, very little informa- 
tion on this subject is available and he 
can hardly be blamed for following along 
in the same rut as his fellow fans. It is 
true, much has been written in regard to 
long and short, high and low aerials, etc., 
but very little has been said in regard to 
how the aerial functions, excepting that 
it is a collector of electro magnetic 
waves. 

Electrical Currents 

The fact is that a current of electricity 
is set up in the aerial when electro- 
magnetic waves cut through it, but as it 
is merely a conductor ending in the air, 
which is an insulator, the question often 
PATTER*/ 




Fig. 1 
arises as to how an electric current can 
flow in an open circuit. It is true (in the 
case of direct or continuous currents) a 
complete conducting circuit must be 
supplied before a current will flow and 
when such a curciut is established, the 
amount of current flowing will depend up- 
on the electrical pressure applied and the 
electrical resistance of the circuit. 

Such a circuit is shown in Figure 1. If 
this circuit is broken at any point, the 
current will cease to flow until it is again 
completed. 

In Figure 2 we have an ordinary elec- 

8U7T0AJ BELL 




trie bell circuit, which forms a complete 
path over which the current can flow, 
with the exception of the button, at 
which point it is open. At any time the 
button is pressed, the circuit is com- 
pleted, current flows and the bell rings. 
The air, being an insulator, will not let 
any current flow until an actual contact 
is made between the two springs in the 
button, by pressing on the knob. 

Thus it is easily seen that an aerial 
circuit, with its open end extending into 
the air, does not supply a complete cir- 

MAXIMVM 
POSITIVE" 




Fig. 2 



MA* I MOM 
tfSG-ATlVE 

Fig. 3 

cuit and consequently a direct current 
cannot be produced in it. 

A direct, or continuous, current can be 
compared to a stream of water flowing 
continuously through a pipe. The char- 
acteristics of an alternating, or oscillat- 
ing, current are different. In this case in- 
stead of being continuous in one direc- 
tion it starts at zero pressure, gradually 
rising to maximum, drops back to zero, 
reverses in direction, rises to maximum 
and comes back to zero, as shown in 
Figure 3. This illustration shows what 
is known as one cycle and the number of 
times it occurs in one second determines 
the frequency. While an alternating and 
an oscillating current are exactly the 
same, low frequency currents are usually 
referred to as alternating currents, while 
those of extremely high frequency are 
called oscillating currents. 

In radio work, currents of very high 
frequency are used. For example, the 
ordinary 360 meter wave used by many 
broadcasting stations, is produced by a 
current having a frequency of 833,000 
cycles and a 300 meter wave has a fre- 
quency of 1,000,000 cycles. Such high 
frequencies can not be obtained with 
ordinary alternating current generators 
and are usually supplied by vacuum 
tubes, which can be made to oscillate at 
the necessary high frequencies. 

Resistance Governs Currents 

Now in alternating current practice, 
the amount of current which will flow in 
a circuit is not only determined by the 
resistance of the circuit and the applied 
pressure, but two other factors enter into 
the consideration. These factors are 
called inductance and capacity. In- 
ductance is caused by the rapid changes 
taking place in the circuit as the current 
rises, falls and reverses as shown in Fig- 
ure 2. The effect of inductance is such 
as to set up a reactive current in the 
conductor, which opposes the applied 
current in direction. This reactive ef- 



fect will depend upon the frequency of 
the current flowing through the con- 
ductor, being greater for high frequencies 
than for the lower frequencies. This in- 
ductive reaction tends to choke back the 
applied current, causing the current to 
lag behind the pressure. In other words 
it supplies another form of resistance 
which is not encountered in direct cur- 
rent work. 

Capacity may be said to also be another 
form of resistance to alternating, or os- 
cillating currents, although its effect is 
negative as compared with inductance 
and by the proper proportion of each, the 
effect of both inductance and capacity re- 
actance can be neutralized, or made zero. 
As the effect of capacity is very essential 
not only in the aerial, but also in the re- 
ceiver, the reader should have a very 
thorough understanding of its cause and 
nature. If two conductors having con- 
siderable surface are placed very close 
to each other, but not allowed to touch, 
and direct electrical pressure is applied 
to them, current will flow for a very small 
fraction of a second, after which it ceases 
to flow. This is due to the fact that the 
large surfaces of the conductors absorb 
some of the current, although the circuit 
is not complete. The current, however, 
will only flow long enough for the con- 
ductors to receive a charge equal to the 
applied pressure, after which no more 
current can flow, for the pressure in the 

GALVANOMETER PLATES 




BffTTERH 



Fig. 4 

conductors is then equal to the applied 
pressure and opposes it. 

The size of the conductors, the distance 
of separation and the quality of the in- 
sulating material between them (in this 
case air) will determine the amount of 
current which will flow into them and 
the length of time required for them to 
receive a charge equal to the applied 
pressure. 

Use of Galvanometer 

Figure 4 shows such an arrangement 
with a battery supplying the pressure 
and a galvanometer connected in the cir- 
cuit. At the instant the current is ap- 
plied, a slight movement of the galvan- 
ometer will be noticed, showing that some 
current has moved in the circuit, although 
this circuit is open (between the con- 




ALTERNATIN& CURRENT 
GENERATOR 

METER 



LINE 



Fig. 5 



10 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



ANTE/WA 



TQANSMITTER 




\\\ \\\ \\ \\ \ 



I I 




4AfT£AAJA 



Figure 6 The magnetic lines being at right angles to the electrical wave travel in. a horizontal plane. 



ductors, or plates). Now if the current 
is quickly reversed, the pressure stored 
in the conductors will act with the cur- 
rent of the battery, or applied pressure 
adding its stored-up pressure to that of 
the battery and the combined pressure 
of both will flow through the gal- 
vanometer in the opposite direction, un- 
til the conductors become charged again. 
Each time the current is reversed the 
conductors will be discharged and charged 
up again in the opposite direction and it 
will be seen that if an alternating, or 
oscillating current is applied to the con- 
ductors, at each change in direction of 
current, a slight current will move, al- 
though the circuit is open. It is true 
that it moves for only a small fraction 
of a second, but it moved and that is the 
important thing. The galvanometer will 
show that a slight current flows first in 
one direction and then the other, as long 
as these reversals in current take place. 
This action of the conductors, or plates, 
is due to the capacity for absorbing a cer- 
tain amount of current in receiving a 
charge. Now it will be apparent that the 
larger the conductors and the closer they 
are together the more capacity they will 
have, causing the current to flow longer 
before they become fully charged. 

Figure 5 represents a condition which 
very often occurs on alternating current 
circuits. An ampere meter placed in the 
circuit near the generator will show some 
current flowing even though the circuit 
is open at the distant end. This is due 
to the capacity of the conductors ab- 
sorbing and discharging current. 
Action in Antenna 

After this discussion on the subject of 



capacity, it becomes a simple matter to 
explain the action of the antenna. The 
energy supplied to the aerial of the trans- 
mitting station produces both electrical 
and magnetic effects. The electrical 
wave is in the form of a strain between 
the aerial and ground which is released 
at each pulsation carrying with it the 
tiny magnetic lines of force which eventu- 
ally reach the receiving aerial and in 
cutting through it, produce a current of 



ground as shown in Figure 6. The mag- 
netic lines being at right angles to the 
electrical wave travel in a horizontal 
plane, cutting through the receiving 
aerial as shown. As each cycle of the 
incoming wave reverses, the lines cut 
through the receiving aerial, first in one 
direction and then the other, producing 
in it, a current of the same frequency as 
that sent out from the broadcasting sta- 
tion. As each impulse is of extremely 




Figure 8. Water analogy of antenna capacity, with relation to wave length. 



extremely low pressure in the aerial and 
the primary coil of the receiving set 
which is included in the circuit. 

The principle involved in the produc- 
tion of this current is similar to that of 
the dynamo, in which the conductors are 
revolved in a magnetic field and made to 
cut through the magnetic lines of force. 
In the case of the aerial the lines of force 
are made to cut through the conductor. 
The electrical wave passes out into space 
in the form of lines from the aerial to the 




Figure 7. Wrong construction of antenna, 
up opposing currents. 



The lines cut in such a manner as to set 



short duration, the capacity of the aerial 
should be enough to allow as great a 
charge as possible, or in other words, 
should be enough to allow it to charge 
completely with each impulse as previ- 
ously explained, in order that entire an- 
tenna circuit may be made to oscillate 
in unison with it. 

As the magnetic lines travel in a hori- 
zontal plane, most of the cutting takes 
place in the vertical part, or lead-in of 
the aerial, the horizontal part on the roof 
acting more as a capacity than as a re- 
ceiver. In fact, if the flat part of the 
aerial is the same height on both ends, 
no cutting of the lines through it will 
take place, as the lines travel in the same 
plane with it, but if the end farthest from 
the lead-in is slightly elevated, then some 
cutting of the lines will take place, al- 
though the current produced in this part 
will be slightly out of phase (later, or 
ahead) with that produced in the ver- 
tical part, but it will be in the same di- 
rection. 

Effect of Height 

If, however, the distant end is con- 
siderably lower than the lead-in end as 
shown in Figure 7, then the current pro- 
duced in this part will be in the opposite 
direction to that in the vertical part and 
the result obtained will be the difference 
(Continued on page 44.) 



RADIO AGE— "THE MAGAZINE OF THE HOUR". 



11 



Interference Rejectors 



By FELIX ANDERSON 

Technica lAssislan I, Radio Age 



23PLA7E VWlABlE gohdemser 



43 PIA7£ VARIABLE (OVDEA/SE/? 



TO 
ANTENNA POST OH/ 
SET 



TO 6-QQVND POST 
ON QECEIV/A/G-SE: 




HONEYCOMB COIL 
SO - 75" 7VRNS 



FSLfX ArVDERSOM 
RAOIO 9VqS 



OOSF COIL 2SOO 71//3VS 
NO 34 DCC ON 3 /N 7V8E 



Figure 4 — The isometric sketch of the tube rejector, illustrated electrically in figure 3. 



IN THE January issueof RADIO AGE, 
the writer gave some practical hints 
on the construction of wave traps, 
and eliminators, useful in tuning out in- 
terference from stations and other 
sources, which met with the approval of 
many fans. The article, while describing 
in detail some of the more simple but 
nevertheless effective types of filters, did 
not comprise two types which are of great 
value in eliminating interference, and 
which are of great help in eliminating sig- 
nals of disturbing nature. 

The writer realizes fully that the aver- 
age fan will not stop at expense or 
trouble when it comes to removing this 
obstacle from his path, and wishes there- 
fore to give detail on the construction of 
two more elaborate types of so-called 
rejectors. 

The first of these two rejectors is a sys- 
tem widely used by the British Marconi 
Company for tuning out interference 



from continuous wave stations. Broad- 
cast stations using tube transmitters are 
included in the category of modulated 
continuous wave transmitters, and the 
rejector shown in Figure 1 is therefore 
of material assistance in eliminating sig- 
nals from a station of that type. 

The only disadvantage that this type 
of rejector has, is its cumbersome and 
clumsy construction, but the relative ef- 
ficiency of a system of its kind greatly 
offsets any constructional or mechanical 
difficulties. 

Procure about four feet of very heavy 
copper wire about the size used for street 
car trolley wire or larger, four switch lev- 
ers, eight switch taps, about ten inches of 
copper strip one thirty-second of an inch 
thick or heavier, one dozen small nuts 
and bolts, a piece of brass eight inches 
long, one-sixteenth of an inch thick and 
about three-quarters of an inch wide, two 
binding posts, and four fixed condensers 



of the mica type of the following ca- 
pacities: .001 MF, .002 MF, .003 MF, 
and .005 MF. You will need several feet 
of bus bar for wiring, a suitable mounting 
board or panel or other arrangement to 
fasten this accumulation of apparatus on. 

Drill a hole large enough for a shaft to 
mount the slider in the panel or mount- 
ing board as shown in Figure 1. If you 
can acquire one of those porcelain gas 
stove handles such as is used on gas burn- 
er stop cocks, use it as a knob to vary the 
slider. Drill holes large enough to fit the 
small mounting screws to the panel 
(which by the way should be large enough 
to accommodate a fifteen inch circle of 
the heavy wire) at regular intervals along 
the circumference of a circle of fifteen 
inches diameter. 

The next step is a feat of strength. 
The heavy wire must be bent into a well 
rounded circle of 15 inches diameter. 
After this has been done, it is carefully 



12 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



4£&AL 



single raw OF HEAVY 

SOLID COPPER UMRE 




as low a resistance factor with respect 
to both alternating current impedance 
and ohmic resistance as possible. 

When the construction has been com- 
pleted to the satisfaction of the above 
specifications, connect the post marked A 
to the antenna, and Post B to the an- 
tenna post of your receiver. It does not 






swircues 



.001 



.002 oo3 



V .oas- B 



1 AEfHAL 



S£T 



-* (tBDUND 



_ ' 6-QOUkJU 

sandpapered, and soldered rigidly to the 
copper strips which are cut from the ten 
inch piece of copper. The illustration 
shows how this is accomplished. The 
slider, constructed from the brass strip, 
should next be drilled and mounted so as 
to run smoothly over the entire arc. 
Drill for the mounting of the switch lev- 
ers, and switch points and make allow- 
ance for the two binding posts. Two 
switchpoints must be used, one to throw 
the condenser into the circuit and the 
other out. 

When all the apparatus has been 
mounted either according to the above 
instructions or to the taste of the builder, 
the instrument should be wired according 
to the diagram shown in Figure 2. The 
isometric sketch of the rejector also por- 
trays clearly the method of wiring up 
such a unit. 

Solder all the connections, and make 
sure that not a poor connection exists in 
the set. The secret of the entire rejector 
lies in the construction to make it possess 



T 



AERJfiL 



.OOOSTMF 



Figure 2 — The wiring diagram of 
the rejector, showing how the unit is 
connected to the rest of the system. 

make a particle of difference what type 
of circuit you are using so long as it uses 
an antenna of the open end type. This 
circuit can be used with loop aerials, but 
the writer hardly deems it necessary to 
use an arrangement of this type with a 
properly constructed loop. 

The rejector is tuned very much in the 
same way as the ordinary wave trap is 
operated. Different settings of the 
switches controlling the condensers, and 
varying of the slider on the inductance 
will reveal a certain well defined point 
where the signal of the interfering station 
is obliterated. 

The receiver is then tuned to any wave 
except that to which the rejector is tuned. 

The action of the rejector is the same as 
that of a wave trap, inasmuch as it con- 
sists of a highly selective parallel tuned 
circuit which is connected in series with 
the antenna lead. The rejector when 
properly tuned to the interfering wave by 
the manipulation of the condenser 
switches and slider offers a very high im- 

HOUeVCCMB COIL 40 TUWS 



pedance to the frequency of that signal, 
while to other signals on other frequen- 
cies, the impedance is negligible. The 
signal not wanted is dissipated in the 
wave trap or rejector, while other sig- 
nals which are not coming in on the same 
wavelength pass through the rejector 
without resistance. 

The rejector may be connected into the 
antenna in the manner shown in Figure 5, 
page 6, of the January, 1924, issue of 
RADIO AGE, where it performs the same 
duties as outlined for the wave trap con- 
nections of that article. 

It may not be amiss to again mention 
that if results are to be obtained with this 
type of filter, the condensers must be of 
low loss construction, the connections 
should be rigid, and it is even a good plan 
to wire the rejector up with wire of as 
great a thickness as mechanical reason- 
ableness will permit. A number 10 or 12 
wire is not any too large, and a strip of 
sheet copper cut into a ribbon about 1—2 
inch wide is vastly superior for connect- 
ing purposes. 

If you can convince yourself that a 
clumsy affair of the dimensions given is 
efficient enough to offset the appearance 
and convictions that radio apparatus 
should be as small as possible without re- 
gard to electrical specifications, we cer- 
tainly recommend your constructing one 
of these rejectors. 

Vacuum Tube Rejector 

The most elaborate of all the inter- 
ference preventors, selectors and systems 
to prevent interference as yet outlined in 
RADIO AGE is the radio frequency am- 
plifier-rejector, which requires more ap- 
paratus than the ordinary detector cir- 
cuits now in use. 

A glance at Figure 3 will reveal that the 
circuit is really nothing more than a 
simple radio frequency amplifier which 
can be connected to the antenna and 
ground posts of any of the conventional 
receiving sets now in use. The circuit is, 
however, really more than that, due to the 
fact that it contains in its plate circuit a 
highly selective wave trap, which in con- 




HOt&VCOMB COIL 
5o~7? TVRMS 



VI 



CHOKE COIL. 
2S00T #34 DCC 
ON' 3 IN 7VSE 



200-400/7) NaAAAAMM/ 

RffiNT/oMBTER ^ I 




OOl MF COND£MSE% 



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Figure 3 — The tube type of rejector is one of unusual merit, and fans who are looking for an elaborate but sure-fire eliminator 
should try the one described herewith. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



13 



Figure 1. 



SMALL COPPeR STRIPS 
SGQBU/&) 10 P/)A£C ) SMfcie 
IP®/ /A/OUCmA/C£ 90LD£Qm 

T07H£SE S77$/ps 



To ser (fla$r&) 



SumtipcvAfrs 




FB6/X ANDERSOK' 



junction with the action of the tube and 
choke coil, acts as a highly selective tuner, 
of the finest degree. 

The action of the 23 plate condenser in 
the antenna circuit is a well known fac- 
tor, inasmuch as many fans are already 
aware of its value in tuning. This con- 
denser in connection with the honeycomb 
coil used as an inductance, form a pre- 
liminary tuning circuit much similar to 
the one described under the title of simple 
series eliminator in the January issue. 
Together with the action of the tube, 
which further increases the sharpness of 
tuning, it is in itself a circuit from which 
average selectivity may be expected. 

The insertion of the forty turn honey- 
comb coil and 43 plate condenser in the 
plate circuit further removes the ob- 
noxious interference, which we are trying 
to eliminate, and this, together with the 
tuning qualities of an efficient receiver, 
forms probably the most surefire method 
to rid one's self of what the amateurs 
term"QRM." 



List of Parts 

The necessary parts for the construc- 
tion of a unit of this type are rather many 
when one considers that it is merely to 
be used as an interference preventer, but 
one should remember that in addition to 
its being a boon as far as selectivity is 
concerned, it is a simple radio frequency 
amplifier of efficient design. The parts 
necessary are: 

1 7x10 inch panel. 

1 23 plate condenser vernier type pre- 
ferred. 

1 43 plate condenser vernier type pre- 
ferred. 

1 50-75 turn honeycomb coil. 

1 40 turn honeycomb coil. 

1 rheostat. 

1 200-400 ohm potentiometer. 

1 tube socket. 

1 radio frequency choke coil wound to 
specifications. 

8 binding posts. 

Bus bar, tube (Western-Electric pre- 



ferred) mounting board and other acces- 
sories. 

The arrangement shown, while spread 
apart to illustrate more clearly the con- 
nections, can be used if the apparatus is 
bunched closely, to make sure of short 
leads, so necessary in the construction of 
radio frequency apparatus. If the builder 
desires he may use his own judgment as 
far as arrangement is concerned so long 
as he observes carefully the rules regard- 
ing the construction of radio frequency 
units. 

The construction is largely a matter of 
personal choice of apparatus, and know- 
ing that amateurs rarely work to given 
dimensions, we refrain from printing 
template instructions or definite measure- 
ments. 

The size of the honeycomb coil in the 
antenna circuit is largely dependent upon 
the size of antenna, and a little ex- 
perimenting with coils of different sizes 
will soon determine which is the proper 
size to use. 

The choke coil is probably the only 
difficult thing to make (here is where the 
{Continued on page 38.) 



14 



RADIO AGE— "THE MAGAZINE >F THE HOUR' 




RADIO AGE— "THE MAGAZINE OF THE HOUR" 



15 



The Old Reliable Circuit With New 

Tuning Unit 



By FRANK D. PEARNE 



MANY of the old time circuits, 
the ones which we used to build 
in the old days when broad- 
casting was hardly known, have proved 
their value over and over again and if the 
truth were known many of the supposed- 
ly new and intricate circuits of the last 
year or two are merely additions, or re- 
arrangements of these old-timers. Some 
of these changes are for the better and 
some for the worse, but the original basic 
principles are still there and may be 
easily recognized if the circuit is care- 
fully analyzed. 

One of the most popular improvements 
was the substitution of the spider web 
coil instead of the large variable induc- 
tances previously used. The principal 
advantage of such a coil is the reduction 
of the distributed capacity which is 
present in straight layer windings. Dis- 
tributed capacity acts like an extra 
load connected across the terminals of 
the coils, using up much of the feeble 
energy received upon the aerial and any- 
thing which tends to reduce it, is sure to 
improve reception, especially in the 
reception of signals from distant stations. 

However, until recently no very con- 
venient method of adjustment has ever 
been applied to such coils and the mount- 
ing and adjusting arrangement was 
usually left to the discretion of the build- 
er and as might be expected, most of them 
were marvelous feats of engineering. 
Nearly all the adjustments were obtained 
by swinging one coil away from the other 
at right angles, the movable coil being 
mounted on some sort of a hinge which 
unless very carefully made, would not 
give the same adjustment two times in 
succession. 

In the circuit shown in the accompany- 
ing drawing, the movable coil is made 



to move in the same plane as the sta- 
tionary coil, making a coupling between 
the two with a flat magnetic field and by 
this method, the lines of force are con- 
centrated, instead of being spread out. 
Because of this concentration, the lines 
do not penetrate to the other parts of the 
set and cause such disturbances as howl- 
ing, nor will they waste their own energy. 

The tuning arrangement shown in the 
drawing was originally invented by Mr. 
Carl Pfanstiehl, president and engineer 
of the Pfanstiehl Radio Service Company, 
back in the early part of 1923, and as it 
has proven such a success in thousands 
of sets produced by him, he has consented 
to show his method to our readers. This 
sliding method of adjustment can be 
adapted to any of the popular circuits 
where the space is limited and will be 
found to give very close and sharp 
tuning. 

In the circuit described, the movable 
coil is included in the plate circuit, and 
acts as a feedback, making the set regen- 
erative, and as by this method its posi- 
tion can be changed so minutely that the 
amplification by regeneration can be 
controlled to a very fine point, which is so 
necessary in getting long distance recep- 
tion. The 23 plate condenser in the 
aerial circuit will also help to a marked 
degree in bringing in the distance. 

While a carbon rheostat is shown on 
the panel, merely for convenience, any 
standard rheostat will answer the pur- 
pose very nicely. The phone condenser 
is used to by-pass the radio frequency 
current, which cannot get through the 
highly re-active windings on the phones. 
Any standard detector tube may be used 
and the filament battery selected will be 
determined by the type of tube used. 

Figure 1 is an isometric drawing show- 




iMlNlfc-i 



v 



H|IW 

-/3 + 



ing the panel arrangement and layout of 
the parts. This can be any convenient 
size of panel and baseboard to suit the 
cabinet which the builder can obtain. 
Figure 2 is a schematic arrangement of 
the circuit showing a list of the necessary 
parts and their different values. 

This circuit in use in Chicago has been 
picking up California and all distant 
points in America. The circuit is not 
unusual and has been thoroughly tried 
out and can be depended upon and the 
total absence of any dielectric material 
in the magnetic field, eliminates loss of 
energy through dielectric absorption, 
and in the reception of distant signals. 
This point is of the most vital impor- 
tance. 



MacMillan's Messages 

An absurd newspaper dispatch was 
published recently to the effect that the 
Aerial League of America was urging 
radio operators to check up and try to 
determine why Dr. Donald B. Mac- 
Millan's radio messages "had not been 
heard in Canada and the United States." 
One Chicago daily gave the "story" quite 
a play and other papers in various parts 
of the country gave it space. 

It apparently had escaped the notice 
of all these editors that practically every 
newspaper in the country for several 
months has been publishing items about 
reception of messages from Dr. Mac- 
Millan. Interesting accounts of how 
Jack Barnsley had received and relayed 
many messages from Canada to the Unit- 
ed States have frequently been printed. 

Denial of the Relay League's aston- 
ishing suggestion was slow in overtaking 
the original misstatement. On Decem- 
ber 17 Kenneth B. Warner, president of 
the A. R. R. L. effectually spiked the 
yarn. President E. F. McDonald, Jr., 
of the National Association of Broadcast- 
ers also sent a statement broadcast, show- 
ing that communications had been re- 
ceived regularly in both the United States 
and Canada. 



LEGEND 
AER/AL 

23 PLATE VERN/ER CONDENSER 
SuJlTCH & SUJOCH7APS 
GROUND 

TUNING UNIT 
GRID LEAk-lSME&OHMS 
6Q/D CONDENSER .00O2ST MF. 

8 AW V/PE TUBE 

9 VERNIER RHEOSTAT 

3 ff/JTTEpy A6-30 V- 
PHONE CQNOENSPR .001 MF 

HEADSET 

ft LAMENT 8ATTERV 



i 

2 

3 
4 
E 
6 
7 



lO 
If 
12 
13 



16 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



a 



NERK!" 



WASHINGTON, D. C— With the 
materialization of the plans for 
the polar trip of the naval air 
cruiser, "Shenandoah," or the ZR-1, it 
has been decided that her original 300- 
mile radio equipment first described in 
these columns last July, is inadequate 
and a brand new transmitting unit good 
for a thousand miles has been developed 
by naval radio engineers. 

If, late in July or August, fans pick up 
the call, NERK, they may shout with 
glee, for it will be the "Shenandoah" 
communicating with one of the far- 
northern radio shore or ship stations. 

Radio equipment plans for the "Shen- 
andoah" include two transmitting sets, 
two receiving outfits and a radio compass. 
The high-powered set which replaces the 
six fifty- watt tubes, includes two 2-kw 
tubes, with an input of 4 kw, and an out- 
put of 2 kw. With this transmitting 
set it is believed several northern radio 
stations such as exist in Iceland, Green- 
land, Spitzbergen and Russia, or our own 
Alaskan stations, can be reached. With 
the powerful receiving sets Annapolis, 
Cordova, Lafayette, Nauen and other 
high-powered stations can be copied, or 
used as points to establish the position 
of the great airship by means of the radio 
compass. This instrument is now be- 
lieved indispensable on this exploration 
trip from a base at Point Barrow, Alaska, 
1,117 miles south of the Pole. 

Besides the high-powered transmitting 
set, an auxiliary medium-range tele- 
graph and telephone set is to be installed 
aboard the aerial cruiser. The telephone 
feature will be utilized for communicating 
with ground stations when landings are 
being made for the immediate transmis- 
sion of orders to the ground crew or op- 
erators at the mooring masts. 

All the radio equipment weighs is 1,023 
pounds, which in itself is believed by 





"Radio Dare-devil" 
Major Edward H. Armstrong, of 
New York, is here shown with a six- 
bulb suitcase receiver. The major is 
seen in summer attire because he was 
snapped at Palm Beach, Fla., where 
he went for a honeymoon. Mrs. 
Armstrong was Miss Marian Macln- 
nis, of Merrimac, Mass. It was Major 
Armstrong who applied the regener- 
ative principle to radio circuits. 



engineers to be a great accomplishment, 
giving a transmitting radius of ap- 
proximately a mile a pound. This is very 
light in comparison to the radio apparatus 
carried by surface vessels of the navy. 
The after-section of the control car will 
be used as the radio shack. Some dif- 
ficulty in locating the radio compass 
where it will be operative and yet not 
hinder the progress of the airship and 
interfere with landings is being en- 
countered, but this problem will be solved 
soon, radio experts declare. 

The plans call for the use of two-base 
ships in the far north, each of which will 
be outfitted with a mooring mast and 
carry radio apparatus for communicating 
with the "Shenandoah" when she is on 
voyages. One of these remodelled tank- 
ers will be sent to Point Barrow, 70° 
north, and the other will in all probabil- 
ity be dispatched to Spitzbergen, where 
it is hoped a temporary radio-compass 
station can be established. Two other 
portable radio-compass stations will also 
be erected as far north as they can be 
pushed. With the two ships, this will give 
the "Shenandoah" five radio compass 
stations of her own from which to check 
her position and progress toward the top 
of the world, even if she fails to pick up 
existing radio stations. 

As has been pointed out previously, 
radio will enable the navy to check the 
position of the airship and if the pole is 
reached to prove it conclusively by cross 
bearings made aboard. Her positions 
could be rechecked later by northern 
stations having radio compasses. This 
eliminates faking of a position not at- 
tained and is a new feature in polar ex- 
ploration made possible by radio. Since 
the Arctic summer is barely two months 
in length, and daylight is believed a neces- 
sary requisite in this venture to the Pole 
by air, speed in establishing the tempo- 
rary radio stations in the north is neces- 
sary, so that the airship need never be 
out of touch with main and auxiliary 
bases. 




AERIALS AND CLOTHESLINES 
Picturing the back of a row of tenements near Jackson Avenue, Long Island City, where the tenants are 
not permitted to string aerials on the roofs. To overcome this objection, a young forest of backyard poles 
in competition with wash poles serve as aerials for the radio enthusiasts. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



17 



Crystal, to Tube, to Loud Speaker 

A Two Stage Audio Frequency Amplifier to Use With Selective Receiver Described in 

January Radio Age 



IN LAST month's description of a se- 
lective tube receiver, evolved from 
our original crystal detector circuit 
of the December issue, we have consid- 
ered merely what may be regarded as the 
essential processes of reception. 

The response of all methods of recep- 
tion can be further improved by straight- 
forward amplification. 

We conceive the most simple to be that 
method which deals with amplification of 
low frequency currents which is called, for 
obvious reasons, as previously discussed, 
audio frequency amplification. Radio 
frequency currents are by no means as 
simple of control and the perfection of the 
type of amplification under discussion is 
advisable before any attempt at the other 
is assayed. 

The method consists essentially of a 
series of audion amplifiers arranged elec- 
trically so that the amplified output of 
each tube is passed on successively to the 
next to be again amplified. Each tube 
with its passing-on coupling is referred 
to as a stage, or step in the amplifier. 

As magnification of tube and battery 
noises, and other disturbances of this na- 
ture, is proportional to the magnification 
of the signal received the number of 
audio frequency stages which are ad- 
visable are two, possibly three. 

Several methods of linking tubes are 



By J. A. CALLAHAN 

possible; resistance, inductance or trans- 
former coupling. We are offering herein 
the latter method as affording the great- 
est degree of increased volume. 

Transformers 

In selection of transformers preference 
should be given to those types which are 
shielded. In view of the low cost of these 
units a discussion for their construction 
does not seem necessary. The proper 
ratio is a six to one on first and second 
stages respectively. It is advantageous 
to connect the second stage of amplifi- 
cation as a push-pull type. This method 
was described at length in the January 
issue of RADIO AGE with a presenta- 
tion of its virtues. 

Switches or jacks are usually provided 
for connecting the telephones either in 
the plate circuit of the second tube for 
full amplification or in the plate circuit 
of the first tube for the use of a single 
stage. In the diagram pictured, jacks are 
shown and are of the three-prong type 
which are preferred by the writer because 
they are more simple to connect, having 
one less contact as a source of disorder. 
This method of jack connection allows 
one side of primary to remain connected 
to circuit; however, with audio frequency 
current there will be no disadvantage of 
dead end or capacity losses. 



If the four-prong jacks are preferred, 
they can, of course, be employed. 

Filament control jacks can be employed 
and do not differ in construction from 
other standard types of jacks, with the 
exception of two additional prongs for 
filament which act in the nature of a 
switch contact to connect A battery to 
filament of tube to be employed. This 
method relieves the necessity for filament 
current switches for detector and ampli- 
fier tubes. It eliminates switches be- 
tween amplifiers and between amplifier 
and detector. It is a saving of filament 
current which under customary opera- 
tion is wasted by leaving tubes burning 
while not in service. It simplifies the 
operation of the receiver. Pushing in the 
phone plug connects the receivers to cir- 
cuit of detector or desired stage of am- 
plification and lights the tube or tubes all 
in one operation. An added convenience 
is found in that once the proper adjust- 
ment of rheostat is obtained it will re- 
main constant. A diagram showing con- 
nection of this type of jacks is offered for 
your convenience, should they be pre- 
ferred. 

As advised for our detector, or tuning 
unit, in the January issue we are still 
adhering to the preference for six-volt 
tubes in th's unit, those known as am- 




£> er¥-3 | 



18 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 




plifier tubes, which differ somewhat from 
the detector tube. 

Dry Cells 

The smaller tubes can be used, with 
dry cells, without necessitating any 
change in the circuit, with the possible ex- 
ception of rheostat resistance. 

The U V 201a or C 301a are recom- 
mended. 

The resistance of rheostat depends 
upon the tube employed and is rated as 
given in the accompanying table. 

W D 11-12 tube 6 ohm rheostat 

U V 199 and C 299..20 to 30 ohm rheostat 

UV 201a and C301A 

15 to 20 ohm rheostat 

UV 201, C301 and 216A 

4 to 6 ohm rheostat 

A "C" battery is advisable because of 
the resulting economy of B battery cur- 
rent and is particularly advantageous in 
increasing volume if the peanut tubes are 
used. This should be four and one-half 
volts, regardless of type of tubes in circuit. 
B battery connection is indicated in dia- 
gram and plate potential can be from 
sixty to 100 volts. 

Difficulties may be encountered in per- 
fecting operation of the amplifier. Some- 
times transformers are defective, often 
through being damaged in shipment. A 
simple test by which condition can be 
determined is employed by connecting 
the primary of transformer in series with 
a 22 H volt B battery and a voltmeter 
which has a reading of from 25 to 50 
volts. Depending upon the make of 
transformer, the reading of voltmeter 
should be between ten and eighteen volts. 
If the meter registers over twenty volts 
the transformer is shorted. If it does not 
register at all some connection is broken 
and in either case the transformer is not 
serviceable and must be replaced. 

The secondary of transformer is tested 
in the same manner. The volt meter in 
this testing should read from five to ten 



4 



|i|i|i|i|i|i||Ihi|i|i|i|i|i|i|i|i!^ 

ZZ'AVOLTS 30 V0I.T5 

volts if effective and if over fifteen volts is 
registered it is shorted. 

Locating Troubles 

If signals are without amplification 
look for a dead B battery or defective 
transformer. 

If no signal is received look for lack of 
contact of jack or for disconnected B 
battery. 

Distorted signals result from inoper- 
ative C battery or defective transformer. 

Now that we have offered you a se- 




lective tuner and an efficient amplifier you 
are going to experience the added joy 
of general participation in the high qual- 
ity of entertainment being broadcast, 
rather than that which is limited to the 
phone method of reproduction, and there 
need be no scramble and argument in 
your generally peaceable family as to 
"whose turn it is to listen-in" because 
you are justified in adding a loud speaker 
to your equipment, knowing that it will 
afford a highly satisfactory performance. 



his hand, often neglecting to make a 
ground connection, and listens in. 

To be sure, he takes what he gets — the 
nearest and strongest station on the air. 
The vest-pocket set comprises a single 
head phone, without leads, and a fixed 
crystal detector, connected in parallel 
with the phone by two short copper 
wires from the telephone terminal. 
Placing the phone to one ear and making 
contact with as good an aerial as he can 
find conveniently by means of his fingers, 
which of course must touch one of the 
two terminals, is all he has to do. By 
this means he has heard NAA time 
signals and set his watch, and also whiled 
away odd minutes by listening to WRC 
or WCAP when they were on the air. 
One day he picked up KDKA. When 
convenient he also makes a ground 
connection at the other phone terminal, 
but he says it isn't always necessary. 
The particular crystal he uses is a com- 
pact unit about the size of a short thick 
lead pencil with binding posts at each 
end convenient for connection with the 
phone terminals. He used to use a tuner 
but as this bulky apparatus didn't im- 
prove incoming signals he discarded it 
as he also did his phone leads and wires 
for connecting with aerial and ground. 
The result is believed to be the neatest 
cheapest and smallest portable set in use. 



Tiny Receiver 

Harold Lane, one of the Washington 
correspondents has what is believed to 
be the simplest complete radio receiver 
yet assembled. He carries it in his vest 
pocket, phone and all. When he is near 
anything which will serve as an antenna, 
he makes a contact, sometimes only with 



If your newsdealer has sold out 
his supply of RADIO AGE you are 
likely to miss just the hook-up that 
you have been looking for. To 
avoid any such chance fill out the 
coupon in this issue and send in your 
subscription. Then you will be safe. 
And don't forget that with each 
subscription at the special price of 
$2.50 a year, we send you free the 
popular Reinartz Radio booklet 
FREE. Address Radio Age, 500 N. 
Dearborn Street, Chicago, 111. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



19 



Interesting Combination Receivers 



ONE of the most fascinating things 
about Radio is that it provides 
such a fruitful field for experiment. 
The art is young, and there are many 
questions yet to be answered. The 
apparatus for the study of these prob- 
lems is already planted in millions of 
American homes, and this paper is ad- 
dressed to those who find pleasure in 
trying new circuit combinations. 

With a small selection of the standard 
apparatus, it is possible to arrange 
many interesting new combinations that 
are not given in the instructions. I 
shall give now a list of the apparatus 
needed for the combinations to be 
described later, and it might be well to 
make mental note of the items which 
you do not have. 

2 — Single circuit regenerative tuners 
1 — Vacuum tube detector and 2 

stage amplifier 
1 — Three stage radio amplifier 
1 — Variable air condenser 
1 — -6 Volt storage battery or 
6 — No. 6 dry cells 
4 — Blocks of plate battery, 22 1-2 
volts each 



By R. H. LANGLEY 

Radio Engineering Dept. General Electric Company 

1 — 3 cell Flashlight battery for bias, 

4 1-2 V 
1 — Homemade loop antenna 
6— Radiotrons, UV 201, UV 201-A 
or UV-199 
— Outdoor antenna and ground 
connection. 
The loop will consist of 8 to 10 turns of 
almost any kind of copper wire, wound 
at 3-8 or 1-2 inch spacing on a wood 
frame 3 or 4 feet square, and arranged 
so that it may be rotated on a vertical 
axis. 

In all the circuits to be described, a 
UV 200 soft detector tube may be used, 
if suitable arrangements are made for 
obtaining the correct plate voltage. 
Eighteen Circuits 
With the apparatus just enumerated, 
there are at least 18 different receiver 
circuits possible. Some will be very 
sensitive, some highly selective and some 
both selective and sensitive. Some will 
be suitable for use in congested districts, 
some will function best for nearby sta- 
tions and some for distant stations. It 
is not possible of course to give diagrams 
of these circuits, but we can classify 



and describe them so that the possibili- 
ties of the various combinations may be 
seen. 

Let us divide the 18 circuits into five 
classes. 

First, on the outdoor antenna with- 
out radio amplification. 
Second, on the outdoor antenna with 

radio amplification. 
Third, on the loop antenna. 
Fourth, using both the outdoor 

antenna and the loop, and 
Fifth, some special arrangements. 
In the first class, that is, on the out- 
door antenna without radio amplifica- 
tion we can list seven different combina- 
tions. Two of these regenerative; the 
other five circuits are not regenerative. 
This, of course, means a great deal in 
signal strength, particularly on the more 
distant stations, but for the sake of mak- 
ing the list clear and easy to remember 
we will take them all together. 

The seven circuit arrangements pos- 
sible on the outdoor antenna without 
radio amplification are as follows: 

First, single circuit tuner, using 
crystal detector. 




LONDON AND LOS ANGELES 
Mr. Kennedy is here shown pointing out the vernier rheostat on his simple three tube honeycomb regenerative 
set. He does all his tuning on this rheostat and on the secondary condenser. He gets Los Angeles and London. 
See photograph on next page. (Kadel & Herbert.) 



20 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



Second, single circuit tuner with 

vacuum tube detector amplifier. 
Third, single circuit tuner, with 
detector amplifier and the regener- 
ative connection. 
Fourth, using the outside condenser 

to make a two circuit tuner. 
Fifth, using two tuners to make a 

two circuit tuner. 
Sixth, using two tuners to make a 

three circuit tuner and 
Seventh, using two tuners and the 
external condenser to make a 
three circuit tuner, with all three 
circuit tuned. 
There are two ways of using the 
external variable air condenser to make 
a two circuit tuner. We may connect 
the variable condenser across the tickler 
coil to make a secondary circuit or we 
may connect the condenser in series with 
the tickler coil to make a primary 
circuit. 

In using two tuners to make a two 
circuit tuner the tickler coil of the first 



and from this to the detector audio 
amplifier. The second combination, 
which by the way is a very interesting 
one, provides a method for using the 
loop in a regenerative circuit. This 
uses the loop and one of the single cir- 
cuit tuners, then the radio frequency 
amplifier and the detector amplifier. 

The fourth class uses the antenna and 
the loop in combination. There are also 
several possibilities here. The best one, 
perhaps, consists in connecting the 
antenna and ground to one of the single 
circuit tuners. The loop and variable air 
condenser are connected to the three 
stage radio amplifier and the detector 
amplifier in the usual way. These are 
two independent circuits, the only con- 
nection between them being that the 
tickler coil in the tuner is connected to 
the tickler terminal on the detector 
amplifier. This combination is quite 
remarkable in performance. The an- 
tenna circuit is brought into resonance 
with the signal by means of the tuner 




A DISTANCE GETTER 
Thomas J. Kennedy, 470 West 159th Street, N. Y., regularly receives 
2-LO, of London, Eng., and KHJ, Los Angeles, with this simple three-circuit 
honeycomb regenerative set. He tunes with the secondary condenser and 
the rheostat of the detector tube, without moving the honeycomb coils 
or the ground condenser. Note how he uses condensers and grid leaks 
across the transformer secondaries to clear up signals. (Kadel & Herbert.) 



tuner is used as a coupling coil and con- 
nected to the input terminals of the 
second tuner. 

In using two tuners to make a three 
circuit tuner, the two tickler coils are 
connected together to form the third 
or link circuit. If we connect the 
variable air condenser in series with 
the two tickler coils, we can then tune 
this intermediate circuit. 

The second class of circuits were those 
on the outdoor antenna with radio ampli- 
fication. For these we use our three stage 
radio amplifier and insert it between the 
tuning system and the detector amplifier. 
This may be done on any of the seven 
combinations which we have just noted 
except possibly with the crystal detector. 
Loop Antennae 

In the third class we use the loop 
antenna. There are several combina- 
tions here; let us notice only two. 
The first is the straight loop circuit where 
the variable air condenser is connected 
across the loop and then connected to 
the three stage radio frequency amplifier 



and the loop circuit picks up energy 
from this tuner antenna circuit. The 
reactions obtained by the tickler coil 
connection make it possible to success- 
fully eliminate very loud nearby stations. 

In the fifth class, let us notice two 
stunts. The first one consists in amplify- 
ing the signal obtained from the crystal 
detector, by connecting in such a way 
that the output of the crystal detector 
goes thru the primary of the first audio 
frequency transformer. No batteries 
are needed in the crystal detector cir- 
cuit. This is a very fine way of obtain- 
ing excellent loud speaker signals from 
nearby stations. The second stunt, 
is the use of a grid bias and a higher 
plate voltage on the amplifier tubes. 
Open the grid circuit and insert a small 
Flashlight battery of say 4 1-2 volts 
between the grid and the filament bus. 
The negative end of biasing battery 
should be connected to the grid and the 
positive end to the filament bus. It is 
then possible to use very much higher 
plate voltage on the amplifier tubes, 



with the result that considerably greater 
amplification is obtained with the same 
or even better quality of reproduction. 
With the UV-201, UV-201-A or UV-199 
radiotrons, the plate voltage may be 
increased to 90 or 110 volts. 
Aerials and Tuning 

There are many people who imagine 
that the loop antenna is a substitute for 
the big outdoor aerial and that the same 
results can be obtained from either. 
This of course is very far from the 
truth. There is a very fundamental 
difference. The aerial is a condenser. 
It is a very large condenser to be sure, 
so far as its physical dimensions are con- 
concerned, but it does not have a very 
large capacity. 

The loop, on the other hand, is an 
inductance. This means that the method 
of tuning the aerial is quite different 
from the method for the loop. The same 
receiving sets will not work interchange- 
ably on either. The single circuit 
tuners are suitable-for tuning the antenna, 
but when we used the loop, we used a 
separate variable air condenser to tune it. 

In these experimental combination 
receivers, it makes very little difference 
which tube we use. The main difference 
between the various tubes is in energy 
consumption in the filament, rather than 
in performance as detectors or ampli- 
fiers. Some are slightly better than 
others in this respect, but the main 
purpose of the newer types is to simplify 
the A battery problem. The UV-200 
and the UV-201 require 1 ampere fila- 
ment current necessitating a storage 
battery. This is expensive and trouble- 
some and requires frequent charging. 
The UV-201-A takes only 1-4 of an 
ampere and can be operated four times 
as long on one charge of the battery. It 
may also be operated from dry batteries. 
The UV-199 tube takes only 6-100 of an 
ampere and can be operated from dry 
batteries with great success. 



Radio "Help Wanted" 

The Government is advertising by 
radio! But, although direct radio adver- 
tising is banned, there are few who will 
object, since the results achieved seem 
to indicate that the public is benefited. 
Every Wednesday night, Mr. Morgan 
of the Civil Service Commission, broad- 
casts from NAA, Arlington, openings in 
government positions and announces 
examinations to be held for every kind 
of a job from that of an unskilled laborer 
to those requiring highly trained scien- 
tists, statisticians and executives. Some 
replies indicate direct results, but as not 
all applicants state how they learned of 
the openings, an exact check is impossible. 

The recent call for apprentices for the 
Washington Navy Yard, however, 
brought several phone calls and mail 
inquiries from fathers and mothers inter- 
ested in securing first class training for 
mechanically inclined sons. 

The openings annually announced 
over the radio phone cover as many as 
1,000 different positions, Mr. Morgan 
states, and he is anxious for those seeking 
Government work to listen in Wednes- 
day evenings at 7:25 and learn what is 
available. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



21 




CRUSADERS 

These radio fans are sure that they can induce others not to interfere with the enjoyment of neighbors by mak- 
ing their regenerative receivers squeal. Miss Helen Dickinson, (seated on table) is getting the signatures of New 
York neighbors to an anti-squeal pledge. (Kadel & Herbert.) 

How to Avoid Interference 



The seventh and eighth of this series of 
radio talks, which have attracted wide 
attention, were presented through Station 
WEAF, New York, by Mr. Hogan, con- 
sulting engineer and past president of the 
Institute of Radio Engineers and author 
of "The Outline of Radio." 

IT IS possible to classify the six 
things that give the most trouble, as 
follows: 

1. Nearby broadcasting stations 
using wave frequencies close to 
that which it is desired to re- 
ceive. 

2. Radio telegraph transmitters of 
the spark type. 

3. Oscillating receivers that pro- 
duce whistling noises. 

4. Distant broadcasting transmit- 
ters that radiate waves having 
frequencies within a few kilo- 
cycles of the frequency being 
received. 

5. Atmospheric discharges, known 
as "strays" or "static." 

6. Induction from lighting, trolley 
or power systems. 

Of these six kinds of interference, the 
first, second and third are the most bother- 
some. Perhaps this interference from near- 
by broadcasting stations is not so great a 
difficulty as is interference from spark 
transmitters, but where it does exist it 
is practically continuous whereas spark 
interference at worst is only intermittent. 



By JOHN V. L. HOGAN 

I suppose that accounts for the fact that 
most of the letters I have received ask, 
in one way or another, for remedies that 
will prevent hearing speech or music from 
one broadcasting transmitter while listen- 
ing to another. In any event, this kind 
of interference is wholly or partly spoiling 
the broadcast reception in many homes 
today and it is doubtless the first that 
we should study in detail. 

There is one very good thing about this 
"crosstalk," as we may call it, and that 
is that it can be very nearly if not entirely 
eliminated by rearrangement of your own 
receiving apparatus. Of course, you 
must be reasonable in what you expect 
from any radio receiver; it would hardly 
be fair for a man who lived only a few 
blocks from WCAE in Pittsburgh to 
expect his receiver to pick up signals 
from KDZE in Seattle without inter- 
ference. That is because WCAE sends 
out a wave of 650 kilocycles and would 
be heard very loudly, whereas KDZE 
sends at 660 kilocycles (only 10 kilo- 
cycles higher) and would produce very 
weak signals at Pittsburgh. On the other 
hand, this Pittsburgh^ man might very 
fairly expect a good receiver to cut out 
WCAE at 650 kilocycles (even though 
very near to him) while he listened to 
WOR in Newark at 740 kilocycles, to 
WEAF in New York at 610 kilocycles. 

In the same way, anyone living any- 
where in or around New York may reason- 



ably expect to be able to listen to any one 
of the four local stations WEAF (610 kc), 
WJZ (660 kc), WOR (740 kc) or WHN (833 
kc) without any interference from any of 
the other three at any time. Many people 
living in the middle West Side district of 
New York have apparatus with which they 
are unable to hear any stations other than 
WJY or WJZ when those transmitters 
are working; but this trouble is not 
hard to cure, for there is no insuperable 
difficulty in getting a receiver that will 
bring in long distance stations such as 
KDKA in Pittsburgh and WJAZ in 
Chicago even when installed within only 
a few blocks of WJY and WJZ. 
Depends on Receiver 
The whole matter of eliminating inter- 
ference from one broadcasting station 
while listening to another comes down 
to the choice of your receiver. There are 
two rules to guide this choice, as follows: 
1 : The nearer your receiver is to 
any broadcasting station, the more 
highly selective it must be to pre- 
vent interference from that station. 
2: The greater the distance you 
desire to receive, and consequently 
the more sensitive your receiving ap- 
paratus is, the higher its selective- 
ness must be to prevent interference. 
Thus you will see that a receiving set 
which is perfectly satisfactory in one 
location or for one service may fail utterly 
when used in another place for another 



22 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



purpose. Radio receiving is very em- 
phatically a matter in which one man's 
meat may be another's poisqn. It may 
be helpful, though to consider a list of 
twelve types of useful radio receivers 
arranged in the approximate order of 
their selectiveness, and I will give you 
such a list tonight. If your receiver is at 
the bottom of the list, don't let that 
fact disturb you, for if it is sufficiently 
selective for your purposes, well and 
good. But even a receiving set that is 
rated half-way up the list might not be 
good enough for some locations, and in 
such cases the only two remedies are 
either to pass the set along to someone 
else who can use it and to get a new outfit 
of better selectiveness, or else to improve 
the original receiver. Here, then, are 
twelve types arranged in the order that I 
believe puts the most selective outfits 
at the top and the least selective at the 
bottom: 

1 : Superheterodyne with closely 
tuned intermediate amplifier. 
2: Multiple-stage tuned radio fre- 
quency amplifier with regeneration 
and with double-tuned aerial input 
circuit. 

3: Multiple-stage tuned radio fre- 
quency amplifier with regeneration 
and single-tuned aerial-input cir- 
cuit. 

4: Multiple-stage tuned radio fre- 
quency amplifier without regenera- 
tion but with double-tuned aerial- 
input circuit. 

5: Simple regenerator with dojjble- 
tuned aerial-input circuit. 
6: Multiple-stage tuned radio fre- 
quency amplifier without regenera- 
tion, with single-tuned aerial-input 
circuit. 

7: Simple regenerator with single- 
tuned aerial-input circuit. 
8: Multiple-stage untuned radio 
frequency amplifier with regenera- 
tion. 

9: Non-regenerative audion detec- 
tor with double-tuned aerial-input 
circuit. 

10: Crystal detector with double- 
tuned aerial-input circuit. 
11: Non-regenerative audion de- 
tector with single-tuned aerial-input 
circuit. 

12: Crystal detector with single- 
tuned aerial-input circuit. 
Remember that this list is arranged 
in the order of selectiveness, as it appeals 
to me. A different list would be required 
to show the relative sensitiveness and a 
still different list to indicate the relative 
ease of adjustment. Still further, bear 
in mind that to warrant its rating on this 
list any particular receiver must be well 
designed and well built; a poorly made 
superheterodyne may be less selective 
than a good single-tuned simple regenera- 
tor. 

Cross-Talk 

Cross-talk between broadcasting sta- 
tions is without doubt breaking up more 
reception than any other single kind of 
interference. People who can at one 
time hear music from some one station, 
and hear it easily and clearly, find a little 
later than some other station begins to 
dominate their receivers and that they 



cannot "tune it out" sufficiently well to 
listen to the first. Perhaps they can 
adjust their receivers so that the inter- 
ference is no louder than the speech or 
music that they desire to hear, but it is 
still there and is intense enough to give 
all the discomfort of "getting the wires 
crossed." 

If you are experiencing this sort of 
difficulty — and I know that thousands 
of you are — make careful note of these 
two points: 

First: The trouble necessarily lies 
in your receiver, for the wave fre- 
quencies of the broadcasting stations 
are far enough apart to permit rea- 
sonable freedom from interference 
in any location. Such interference 
is not the fault of any broadcasting 
station nor of the assignment of 
wave frequencies. 

Second: Either your receiver is of 
a type which cannot possibly have 
adequate selectiveness for elimina- 





/f 1 




■ 


1 


j|f / 


\l 






\\m 


V 





60 CENTS 
John P. Buckley, scientist with 
the U. S. Bureau of Standards, 
completed this crystal detector and 
he claims they could be made and 
sold in quantities at sixty cents 
each. (Fotograms.) 

tion of the interference in your 
locality, or it is so designed that its 
selective power is less than your 
particular type should have. 
These two points state facts that 
cannot be controverted, and it is just 
because of that that we can all afford to 
be optimistic about cutting out this cross- 
talk interference. If this trouble did not 
lie in your receiving sets it might be a 
hopeless job to get rid of it; since it is 
necessarily the fault of your receiver, it 
can be cured right in your own home. 

Some of you may be inclined to doubt 
the possibility of cutting out interferring 
stations which send on waves close in 
frequency to the one you want to hear. 
People have said to me: "I paid $250 
for my radio set, and if it won't pick 
up WCAF while VVEAF is sending I 
don't believe that anything will." The 
answer to this is that character is what 
makes a radio receiver good. Dollars 



have little more to do with it than with 
the making of a man. People in your own 
neighborhood, using relatively inexpen- 
sive outfits of good design, are cutting 
right through interference that is troub- 
ling other folks whose sets, in spite of 
their higher cost, are poorly laid out. 

Last week I listed twelve general types 
of radio receivers, in the order of their 
selective ability. Nearly every set now 
in use falls into one of these twelve 
classifications. If your set is low on the 
list, and if you suffer from cross-talk 
interference, perhaps you will have to get 
a more selective type before you can cut 
it out. The probabilities are, though, 
that your set is not as good as it should 
be even in its own type. Therefore 
your first step should be to make cer- 
tain that your outfit is of good design. 

Spark Transmitters 

Before we go into the practical things 
that can be done to improve receiver 
selectiveness let us give a moment to 
the second worst kind of program- 
smasher, which is the spark radio-tele- 
graph transmitter used in ship-and-shore 
wireless. Those of you who have good 
receivers may disagree with my rating 
this spark transmitter as the second 
worst source of interference, for to you 
it is by far the most aggravating. But 
that is because you have already over- 
come trouble number one (cross-talk); 
our unfortunate friends whose receivers 
are so poorly selective that they cannot 
listen comfortably to any but the nearest 
or loudest broadcasting station are very 
numerous, and we must give them first 
aid. 

The fact is, however, that by improv- 
ing the selectiveness of your receivers 
you will greatly decrease the Morsecode 
dot-and-dash spark station interference 
that you now hear. You will never 
eliminate it completely, however, for 
spark transmitters will break through 
and produce disturbances in the most 
highly selective broadcast receivers that 
can be built. The only real cure for spark 
station interference is to eliminate the 
spark transmitters themselves. That 
very thing is going on from day to day, 
so you should all be able to note a con- 
tinued improvement as progress is made. 
Since any increase in receiver selective- 
ness will aid in reducing both cross-talk 
and spark interference, let us see what 
can be done in this direction. First 
we should consider the last or least 
selective receiver on the list I gave last 
week, No. 12, the crystal detector with 
single tuned aerial circuit. Lots of 
people are using these outfits, and in 
some locations they work very well if 
they are properly put together. If you 
have one, and if it is not performing to 
your taste, you can probably improve 
it by putting a variable condenser in 
series with your aerial circuit, i. e., 
between the lead-in of your aerial and 
the binding post on the set to which the 
aerial was connected. Then use as much 
of the tuning coil as you can and do the 
tuning on the variable condenser. A 
still greater improvement can usually 
be made by connecting the crystal 
detector and telephone side-circuit across 
(Continued on page 41.) 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



23 



Little Things That Help 





SOLDERING HINTS 
Poor soldering will ruin the best of sets. Picture at the left shows how to make sure your iron is hot enough. 
Hold it five inches from your face and if you can feel the heat, you are ready. Be sure your iron is clean. It may 
be cleaned easily with a file, as shown in the picture at the right. (Kadel & Herbert.) 



Receiver Essentials 

Many radio fans are constructing their 
own receivers, some of which work well, 
and some which are tolerated merely 
because the builder has not the necessary 
funds to make a new one, says Beverly 
Dudley, member of the American Radio 
Relay League. For the construction of 
a receiver which is to work entirely 
satisfactorily, a thorough knowledge of 
radio principles is essential, but one may 
get on well with a few pointers and his 
own common sense. 

The essentials of a good receiver are: 
(1) Sensitivity, (2) Selectivity, (3) Ease 
of control, and (4) Moderate cost. To 
combine all of these features is not as 
simple a matter as it may seem. 

First of all, a receiver must be sensitive. 



This means the use of vacuum tubes, 
and radio frequency amplification or 
regeneration. For a single tube set, 
regeneration is quite a desirable, almost 
necessary application. There are num- 
erous regenerative circuits to choose 
from, but for short wave reception a 
circuit in which regeneration takes place 
by use of a tickler is most satisfactory. 
Regeneration is secured by means of the 
absorption method, which offers some 
advantages. 

Two Circuit Tuner 
For selectivity, a two circuit tuner 
seems to be the only one worthy of con- 
sideration. Tests made last winter 
showed a single circuit tuner to bring in 
the stations a trifle louder, but the 
tuning was so broad that local and loud 



broadcasts could not be eliminated. 
Even a few amateurs who work on 200 
meters were heard on this tuner, when 
tuned for the broadcasts. It is of no use 
to get loud signals, if you cannot pick 
out the desired stations to the exclusion 
of the rest. The main objection a radio 
fan has to a two circuit tuner is the addi- 
tional control. 

Tuners may be made in such a way 
as to afford the simplicity of the single 
circuit tuner with the selectivity of the 
loose coupled tuner, by making the 
primary of the circuit aperiodic. That is 
to say that the primary is not tuned at 
all. ■ This untuned primary consists 
of from one to five turns of wire wound 
over the secondary coil, or coupled to it. 
These turns may be tapped or not. 




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SOLDERING THAT HOLDS 
The picture on the right shows how the point to which the connection is to be made should be cleaned with 
a piece of sandpaper. On the left picture shows how the iron is used after a little soldering flux has been applied 
to the contact point. The iron should not have too much solder on it and after the connection is soldered and 
cooled the connection should be wiped off with a little alcohol and a tooth brush. (Kadel & Herbert.) 



24 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



The Reinartz tuner uses a tapped but 
untuned primary. This is a very satis- 
factory method of coupling the primary 
and secondary circuits. 

Ease of control is very essential, 
especially to the radio amateur in his 
traffic work. One cannot tune a receiver 
all evening merely to hear the bed-time 
stories from Radioville, two miles away. 
Don't have seventeen tuning controls 
on your receiver; three is plenty. A 
receiver may be — though they usually 
are not — selective with but one tuning 
control. Don't however, sacrifice effi- 
ciency for ease of control. 

As to the cost: buy inexpensive parts 
if necessary; not cheap parts; there's a 
difference. The cost of many receivers 
could be kept down by taking off a lot 
of the trimmings; a receiver doesn't 
need voltmeteis or bezels mounted on its 
panel. 

Be sure to purchase a good variable 
condenser. The one with the least parts 
is all right. One cannot upon merely 
examining a condenser tell its electrical 
efficiency. A variable condenser should 
be mechanically good. Hard rubber is 
much better for insulation on a condenser 
than porous, absorbent fiber. Get good 
mica insulated fixed condensers if you 
value the quality of the signals you 
desire from your set. See that the fixed 
condensers are well made and firmly pres- 
sed tight. A fixed condenser the capacity 
of which varies is worse than nothing. 



Amateur Records 

Hartford, Conn. — By virtue of recent 
two-way amateur radio contacts estab- 
lished by Kenneth B. Warner, secretary 
of the American Radio Relay League, 
England comes to the forefront among 
nations of the world that can now com- 
municate across the Atlantic through 
radio stations operated by citizen ama- 
teur radio men. Nine complete messages 
have been sent across the ocean on a wave 
length of 100 meters between Mr. 
Warner operating station I MO here and 
J. A. Partridge owner of the English 
amateur station 2KF situated in London. 
There is no question but what amateur 
two-way transoceanic traffic has opened 
up a new field of no less importance than 
the early successes, showing the possibili- 
ties of amateur radio, and not a few of 
the old time hams, whose calls were 
famous in the old spark days, are bound- 
ing back "on the air" to partake in 
international thrills. The tests are spoken 
of as the dawn of a world amateur 
relay. 

Kenneth B. Warner, secretary of the 
League, estimated today that a total of 
sixty messages had been transmitted 
across the Atlantic since the first two-way 
contact was made between amateur 
stations 1MO in Hartford and 8AB in 
France the night of Nov. 27. The signals 
of 8AB have been loud and scores of ama- 
teurs are hurriedly bringing their receiver 
down to the 100 meter wave length. 

A radiogram received at League 
Headquarters stated that amateur 
station, 9ZT, operated by Donald 
Wallace, assistant manager of the 
Dakota division, had been in two- 
way contact with the French ama- 
teur and messages had been ex- 
changed reliably. Deloy is believed 
to have transmitted a total of 
thirty-three messages. 



9,563 Miles! 

Hartford, Conn. — An amateur radio 
message from France to the North Pole 
has covered the farthest distance ever 
traversed by an amateur relay, arriving 
safely in the ice-bound cabin of Captain 
Donald B. MacMillan's schooner "Bow- 
doin" after a 9,565 miles journey. 

The same night after Monsieur Leon 
Deloy at Nice, France, transmitted a 
message to the Arctic explorer, a repeti- 
tion of the dots and dashes came in on 
the headphones of Donald Mix, radio 
operator for MacMillan, 11 degrees from 
the pole and inside the aurora. 

In order to reach Refuge Harbor, 
Greenland, the message took a round 
about course across the Atlantic to South 
Manchester, Connecticut, where it was 
received by John L. Reinartz, operating 
amateur station IXAM. Reinartz gave 
the message by telephone to Boyd Phelps 
of Hartford, who relayed it to 6XAD 
at Avalon, Catalina Island, off the coast 
of California. Thence it was sent to 
Jack Barnsley of 9BP, Prince Rupert, 
British Columbia, who finished the relay. 

The distance covered by each relay 
was about as follows: Nice to Hartford, 
3,500 miles; Hartford to Catalina Island, 
2,500 miles; Catalina to Prince Rupert, 
1,305 miles, and Prince Rupert to Refuge 
Harbor, 2,260 miles, making the greatest 
amateur relay mileage. 

In this remarkable record the French 
amateur used two foreign model tubes 
with a 25 cycle plate supply and an input 
of about 400 watts. The receiving set 
used by Reinartz was home-made with 
his own type of circuit. Phelp's set was 
a Tuska 220 receiver. Mr. Mott of 
6XAD used a Grebe CR 13 for receiving 
and a quarter kilowatt tube for trans- 
mitting. Canadian 9BP used one 50 
watt tube for sending, while the North 
Pole receiver is a Zenith "3R." 




HEARD ENGLAND 
Everett L. Battey's friends did not take his little one-tube set very seriously until recently, when he picked 
up three English stations. Everett's home is at Wollaston, Mass/ He logged Bournemouth, Cardiff and London 
in one day. He uses a dry cell. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



25 



The Superdyne Receiver 



IN a recent talk, before the American 
Radio Relay League in Chicago, Mr. 
C. D. Tuska, President of the C. D. 
Tuska Company, gave interesting details 
about the superdyne receiver — a new 
circuit developed by Robert S. Miner of 
the Tuska laboratories. 

Mr. Miner, known to radio amateurs 
as IRU, almost a year ago started to 
work on a receiver that would give re- 
sults which would surpass the regenera- 
tive receiver and the many radio fre- 
quency outfits he had tested. 

In seeking for this new super circuit, 
he and his associates investigated all of 
the latest circuits and 
every modification of 
regenerative, radio fre- 
quency and other cir- 
cuits about which they 
had information. In 
Mr. Miner's opinion, the 
only trouble with radio 
frequency is that it is 
not possible to get suffi- 
cient amplification per 
stage, and he decided to 
locate the difficulties and 
then to overcome them. 

When the superdyne 
circuit was being per- 
fected it became evident 
that resonant circuits 
must be used, but as 
soon as this was done 
the tubes started to 
oscillate and spoiled 
everything so that the 
investigators were i n 
what might be called a 
"vicious circle." The 
method used to over- 
come this difficulty was 
put in the conventional 
Armstrong feedback but 
feed the energy back in 
the reverse direction or 
negatively. The circuit 
was given just enough 
feedback to offset the 
positive capacity feed- 
back of the tube. This 
stopped oscillation and 
made it possible to 
secure absolute resonance 
between the grid and the 
plate circuits. Not only 
was resonance secured, 
but the maximum impedance in the plate 
circuit was used which means the biggest 
voltage impulse which it can be hoped 
to build up. 

The superdyne circuit is shown in the 
accompanying illustration. "RC" is the 
resonant circuit of the grid. "WC" is 
the resonant circuit of the plate while 
"XY" is the reverse feedback which 
stops oscillation. The detector is con- 
nected as shown. After it was found 
what the possibilities were with this cir- 
cuit, experiments were made to see if it 
could be improved by changing the con- 
stants. All of the stages of increasing 
capacity and decreasing inductance as 
well as the reverse, were gone through. 
Every sort of coupling and every con- 
ceivable manner of turns ratio was tried. 



Hundreds of separate experiments indi- 
cated that the successful operation of 
the circuit depended to an extremely high 
degree on following dimensions carefully. 
Not only does this apply to instruc- 
tions about sizes of wire and dimensions 
but in addition care must be taken not 
to parallel the grid and the plate wires of 
the radio frequency stage. These wires 
must be kept at right angles and as far 
apart as possible. If the reverse feed- 
back coil is coupled too closely to the 
grid coil the capacity between the grid 
and plate windings exceeds the negative 
magnetic feedback and the set will not 



The dimensions and constants of the 
various coils and condensers are shown 
in the accompanying table. Reception 
on the detector has not 1 een particularly 
successful probably due in part to the 
capacity of the phones on the unground- 
ed circuit. When operating with a small 
indoor antenna, the filaments should be 
grounded and the antenna connected to 
the grid of the first tube leaving out the 
antenna coupling turn. With this meth- 
od, phones on the detector will probably 
be entirely satisfactory. 

The maximum results can be obtained 
after the operator has learned how to 




Audio 
Amplifiers 



SUPERDYNE 
Photograph of the assembled superdyne and diagram of wiring arrangement of this 
interesting receiver. As stated in the accompanying article the manufacturers^are 
ready to assist fans in making this set if they desire instructions. 



work. It is extremely important to 
avoid this trouble so care must be taken 
to copy exactly thespecificationsoutlined. 



Secondary 



carefully adjust the circuits but it is not 
possible to get these results until one has 
had someexperience in tuning faint signals. 



Antenna 

Tickler 

Plate 

Reactance 

Condenser 

Condenser 





COIL DATA 


























Micro- 


Coil Form 














henries 


0. D. 


Winding 


TURP 




WIRE 


TAPS 




4" 


IK" 




42 


No 


22 D.S.C. 


0.20.42 


273 


Over 


Turns 














Sec. 


Spaced 
















M" 




4 


No. 


22 D.S.C. 


0.4 






Ball 














i-H" 


Motor 


18x2- 


-36 


No. 


22 D.S.C. 


0.36 





1H" 



46 No. 22 D.S.C. 0.25.46 264 



(Grid) Tuska Type 271 23 Plates Maximum Capacity .000482 
Plate Tuska Type 271 23 Plates Maximum Capacity .000482 



Wave Length Range (Approx.) 176-358: 310-660. 



26 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



The astonishing part about this outfit 
is that it operates without an antenna 
and gives signals of sufficient intensity 
to be heard through the use of a loud- 
speaker. In Hartford, Connecticut, with- 
out the use of an antenna or loop or ca- 
pacity of any sort, other than the usual 
ground connection, broadcast has been 
heard on a loud speaker from Chicago, 
Davenport, Kansas City, and nearer 
stations. Havana, Cuba, has been ob- 
tained without an outside aerial. 

Desiring to compare this set with some 
of the sensitive sets on the market it was 
recently taken to Washington and a 
series of tests made. First, a constant 
artificial source of power was set up. 
This was tuned on a regenerative re- 
ceiver and the audibility measured 
around 50. With the same power, the 
same tubes, batteries, etc., the super- 
dyne receiver showed an audibility of 
over 200. The same two outfits were 
tried under similar conditions with a 
broadcasting station as the source of 
power. Here the regenerative receiver 
showed audibility of about 60, while 
corresponding conditions showed the 
superdyne receiver to have an audibility 
of 10,000, which was the end of the meter. 

The next test was of a more practical 
nature. Here the superdyne receiver 
under actual receiving conditions was 
compared with the naval six-tube uni- 
versal radio frequency amplifier. The 
signals with the four-tube superdyne 
were probably three to four times louder 
than with the six tubes of the navy am- 
plifier. 

The last experiment was the most 
astonishing of all. In this test the four- 
tube superdyne was compared with the 
eight tubes on a super-heterodyne re- 
ceiver. Some of the signals on the super- 
heterodyne surpassed this new circuit 
while in other cases the superdyne ex- 
ceeded the super-heterodyne. Taken all 
in all, and being very conservative, Mr. 
Tuska believed that the best that could 
be said for the super-heterodyne was that 
the signals may have been slightly louder 
using the eight tubes than they were 
on the superdyne with four tubes. 

In operating this circuit it has been 
found that it is highly desirable to adjust 
the plate circuit for the wave length 
to be received, then operate the reverse 
feedback coil, which has been called a 
"stabilizer", and the grid circuit in ex- 
actly the same manner as a regenerative 
receiver is operated. By carefully ad- 
justing the reverse feedback against the 
positive capacity feedback astounding 
degrees of amplification can be gotten. 
It has been figured that the voltage 
amplification per stage probably runs in 
the neighborhood of 100 times. One 
tube of radio frequency regeneration of 
the old style rarely exceeds a voltage am- 
plification of eight or nine times. 

In order to simplify the operation the 
makers have omitted any tuned antenna 
circuit and simply used four turns of 
wire which are closely coupled to the grid 
circuit. This impulse excitation method 
of tuning seems to be sufficiently se- 
lective, probably due to the selectivity 
of the two resonant circuits. 



Numerous attempts have been made 
to simplify the adjustments of the re- 
ceiver, such as using fixed reverse feed- 
back and gearing the two tuning conden- 
sers together, but this method de- 
creases the sensitiveness of the receiver. 
The closed circuits do not affect each oth- 
er's wave lengths, but the feedback varies 
with the wave length received. The 
reverse feedback has an appreciable effect 
on the grid circuit tuning. Fortunately, 
however, the plate circuit remains ab- 
solutely constant and may be calibrated 
in terms of wave lengths. 

While the Tuska company expects 
to market complete superdyne sets, it 
is willing to assist amateurs building 
their own sets and will be glad to hear 
of successful efforts. 



The Proposed Radio Legislation 

Washington D. C. — There will be no 
general radio conference in Washington 
in the near future Secretary Hoover has 
announced. The Commerce Depart- 
ment is rapidly completing the details 
of a tentative regulatory radio bill 
based on the old White Bill he explained. 
He believes that this can best be done by 
government officials without further 
conference. Practically all the sug- 
gestions offered by representatives in 
the several lines of radio work presented 
at last year's conference will be incorpo- 
rated the Secretary indicated pointing 
out that conditions have not changed 
materially since last year except that 
the number of transmitting stations has 
increased. 

When it is attempted to draw up 
legislative recommendations or bills with 
a large body of diversified interests it 
usually takes several months. Early 
action on the new radio bill is necessary. 




HIGH LIFE 
This experimental radio station 
was built in a treetop by two Oak- 
land, Calif, boys. They say recep- 
tion conditions are so good up 
there that a fellow can almost see 
the ether waves coming. (Keystone) 



A few days ago a delegation of radio 
interests representing the press clubs, 
engineers, broadcasters, and amateurs 
called upon President Coolidge and the 
Secretary of Commerce urging that a 
general conference be called in an effort 
to reduce interference from ships affect- 
ing commercial amateur and general 
broadcasting. The Secretary explained 
that interference was decreasing due to 
the voluntary adoption of regulations 
laid down last year and that the Depart- 
ment was striving to remedy present 
difficulties through revising the White 
Bill which was passed by the House 
last session. Any recommendations 
which the committee desired to make in 
writing the Secretary said would be 
considered by the Department Officials 
now working out the revisions to the 
existing radio laws established in 1912. 

Officials of the Government point out 
that many difficult questions arise when 
regulatory legislation is attempted. Such 
questions as monopolistic control it is 
believed should be handled by courts 
under existing laws and not incorporated 
in radio legislation. 

The prohibition of operation by aliens 
if injected into radio legislation would 
tend to handicap American radio develop- 
ment commercially in foreign countries 
and could be regulated without being 
covered in a radio bill. 

The question of whether or not radio 
is a public utility is not essentially 
necessary in a law which should be regula- 
tory it is believed. 

Some definite standards of operation 
and equipment especially in the commer- 
cial fields must be included however, 
it is asserted so that Secretaries of Com- 
merce will have some basis for their 
decisions as to whether an existing 
station may continue operation in the 
event a new company desires to enter the 
field or whether it must cease operating 
to permit the opening of another station. 
The amount of traffic might or might not 
demand more than one station and 
efficiency would be questioned. 

Many phases of development indicate 
that broad latitude must be granted to 
the Commerce Department but stand- 
ards of requirements and service in the 
public interest should be made clear for 
the future expansion it is believed. 

Recently new interference problems 
have arisen over which the Depart- 
ment has no control under existing laws. 
Complaints received report interference 
from regenerative or re-radiating receiv- 
ing sets, violet ray machines, electrical 
precipitating plants, bell-ringing mag- 
netos on telephone lines, and leaking 
insulation on power transmission lines. 
Government regulations should it is 
believed give the Department power 
to prevent such interference. 

After the presentation of the tentative 
bill in the House and its assignment to 
the Merchant Marine and Fisheries Com- 
mittee it is understood that public 
hearings will be held at which time all 
interests may appear to present their 
suggestions and recommendations. 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



27 



An Inexpensive Homemade Battery Charger 

By F. D. PEARNE 



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77?e constructional and assembling details of the Noden Valve Electrolytic Battery charger. This type of rectifier is designed for 
use in homes where the 1 10 volt house lighting current of the alternating type is available. 



ONE of the most essential require- 
ments of a radio set is some 
kind of a charging apparatus 
which will keep the storage battery 
charged at all times. This is compara- 
tively easy where the electric lighting 
circuit is of the direct current type, 
but unfortunately for the radio fan, most 
lighting circuits use the alternating 
current and before a battery can be 
charged with this current, some method 
of rectification must be used. Various 
devices for this purpose are now on the 
market, some of which are£sold a t 
reasonable prices, while others are really 
expensive, and as the average radio fan 
usually has plenty of outlets^for his spare 
change, I am going to describe a rectifier 
which any amateur can build at an ex- 
pense of less than $3. 



This outfit is known as the "Noden 
valve" and will answer the purpose 
very well and in fact is really better than 
some of the rectifiers one may buy, for 
the reason that it rectifies both sides of 
the alternating current wave, which 
some of the standard outfits do not do. 
The materials required consist of four 
ordinary quart size mason jars, such as 
are used for putting up preserves; four 
pieces of sheet aluminum one-eighth of 
an inch thick; four pieces of sheet lead 
of the same size and thickness, four 
wooden tops to cover the jars, a few 
brass machine screws and nuts, and 
about two and one-half pounds of phos- 
phate of ammonium. 

First cut out four plates of good soft 
sheet aluminum, six inches long, two 
inches wide and one-eighth of an inch 



thick. Bend one end over, one-half 
inch as shown at "A", Figure 1. Drill a 
hole through the center of the part which 
is turned over. This should be drilled 
with a No. 18 drill which is large enough 
to allow an 8-32 brass machine screw to 
pass through it. These plates should 
be made of soft aluminum for the reason 
that hard aluminum will crack and break, 
if bent at a sharp angle. Next cut out 
four pieces of sheet lead of the same 
size and shape as the aluminum pieces, 
and drill holes of the same size in the 
same place. 

The wooden tops for the jars should be 
turned out of hard wood. The flange 
should be three inches in diameter and 
one-half inch thick and the smaller part 
is two and three-sixteenths inches in 
diameter and one-quarter inch thick. 



28 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 




Q/f?£CT 
CURRENT 
TERMINAL- 




LAMPS CONHeCTBD 
A (\ IN PARALLEL 




DIRECT CVRRENT 

TERHINAL. 



+ 




ALTERNATING- CURRENT 



ALTERNATING CURRENT 



FIGURE a. 



The wiring diagram of the jars and the method of connecting the lamps into the circuit to control the charging rale of the rectifier. 
Full details for the construction and operation of this unit appear herewith. 



This small projection is to extend down 
into the jar and will just fit into the 
neck of the quart-sized fruit jar. If any 
other kind of a jar is used, this size 
should be changed to suit the case. 
If it is not convenient to turn these tops 
out in a lathe they can be made of two 
pieces cut out with a jig saw and fastened 
together with screws, but these screws 
must be so located that they do not 
interfere with the holes which are to 
be drilled, as shown at "B," Figure 1. 
Now mount one aluminum plate and one 
lead plate on each of the tops as shown 
at "C," Figure 1. These plates are held 
in place by 8-32 brass machine screws, 
one and one-half inches long and fastened 
with a nut on the other side. The nut 
should be turned up very tight so that 
the plate is held rigidly in place. Another 
nut on top of the first one serves as a 
binding post to which the wires will be 
connected later. 

After all four units are complete 
the part of the plates which was turned 
over, as well as the screw heads and 
the part of the wood which goes down into 
the neck of the jar should be coated with 
melted wax, or paraffine to prevent any 
gas or fumes from the solution cor- 
roding the screws, thereby causing a 
poor joint. Next, make up the solu- 
tion with which the jars are to be partly 
filled, make a saturated solution (all the 
water will dissolve) of distilled water and 
phosphate of ammonium. It is necessary 
that the distilled water be used as it will 
not work if the water contains any im- 
purities. 

Fill the jars with this solution to 
within about one inch of the top, that is, 



the solution should be within one inch 
of the top when the plates are in the jars. 
It is a good plan to measure out enough 
water to fill the jars three-quarters full 
and then add the phosphate of ammon- 
ium, until no more can be dissolved. 
In dissolving this chemical, it should 
not be stirred with a metal spoon ; use 
a piece of glass, so as to make sure that 
no impurities get into the solution. 
Figure 2 is a diagram of the circuit, 
which shows how the connections are 
made. The aluminum plates are marked 
"A" and the lead plates are marked 
"L" respectively. Lamps are connected 
in the circuit, which allow only a certain 
amount of current to pass from the 
alternating current wires to the rectifier. 
Each lamp added in parallel as shown 
will allow more current to flow. The 
direct current is taken off at the junction 
between the jars as shown. To recharge 
the battery, connect the positive direct 
current terminal to the positive terminal 
on the battery and the negative direct 
current terminal to the negative terminal 
of the battery. 

The action of this rectifier is based 
upon the principle that the current will 
not enter the solution through the 
aluminum plate. It will enter the solu- 
tion from the lead plate and flow out 
through the aluminum, however. Let us 
for example say that the circuit shown in 
Figure 2 is connected to a source of alter- 
nating current supply. If the first 
impulse comes in on the side of the cir- 
cuit in which the lamps are placed, 
the current will not enter the aluminum 
plate in the jar on the left side, but will 
enter the lead plate on the right side, 



flowing out of the aluminum plate. It 
cannot enter the cell below it, because 
of the aluminum plate, but will flow 
out over the direct current terminal, 
through the battery and back on the 
negative direct current terminal, through 
the lower cell on the left side to the 
other side of the alternating current. 

The next impulse is in the reverse 
direction and comes to the lower set 
of cells. The aluminum plate in the 
left hand cell prevents the current 
entering so it takes the path through 
the right hand cell, coming out of the 
direct current positive wire again, 
through the battery, back into the nega- 
tive direct current terminal, through 
the upper left hand cell, to the other side 
of the alternating current line. Thus it 
will be seen that the direct current ter- 
minal on the right side of the draw- 
ing will always be positive, no matter 
which way the alternating current flows. 

This rectifier will give very good 
service and will put a good charge 
in the battery in twenty-four hours. 
A small hole should be drilled in the 
wooden tops to allow any gas to escape. 
As it will be necessary to "form" the 
plates before the rectifier will function 
properly, the two direct current posts 
should be connected together for about 
ten hours while the alternating current 
is on, so that perfect rectification will 
take place when the battery is con- 
nected in the circuit. After the plates 
are once formed, then the battery may 
be connected on the terminals at anytime. 
A more efficient method is to use a toy 
transformer, connecting the primary 
{Continued on page 47) 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



29 



\VMat the 




stets 



ate Doing 




Broadcast Records 

AMERICAN broadcasting stations are 
reaching out to such vast distances 
that it begins to appear that voice-radio 
communication with points up to 5,000 
miles soon will be regarded as common- 
place. The recent transatlantic tests 
called general attention to communica- 
tion with English stations. But England 
had heard American broadcasters re- 
. peatedly before these tests and American 
receivers had frequently tuned in and 
picked up English stations. 

To WDAP, the Chicago Board of 
Trade station, belongs the credit of 
having entertained an English listener 
throughout an entire program of several 
hours. The operator who received this 
Chicago program was Thomas E. Ham- 
blett, Windle Mount, Hard Lane, St. 
Helens, Lancaster, England. It may 
be difficult for Americans to understand 
how any message, much less a radio, 
program, could find a Britisher who 
was hidden behind such a complicated 
address as that, but Mr. Hamblett was 
found out not only by WDAP but by 
KDKA, Pittsburgh. On September 25, 
Mr. Hamblett was listening to KDKA 
at 1:57 a.m. He wrote to KDKA saying 
he tuned out after twenty minutes be- 
cause the market reports had driven 
him away. KDKA reached several 
other English listeners. 

Reception of WGY, Schenectady, 
was so successful in Queenstown, Ireland, 
during the transatlantic tests on the 
morning of November 27 that A. N. C. 
Home was able to make a fifteen-second 
log covering the transmission from the 
opening announcement to the "sign-off." 

In his letter to the General Electric 
Company station, Mr. Home stated 
that reception was made on three valves 
— dectector and two low-frequency, with 
an aerial twenty-five feet high and 250 
feet long, inclosed by tall trees. He 
explains that he has studied radio for 
the last ten years and that the highest 
degree of accuracy was aimed at in re- 
cording his observations. 

In his log Mr. Home mentioned that 
the concluding number of the program, 
"God Save the King," was "good." 
That is an odd thing about radio. The 
patriotic hymn, "America," becomes 
"God Save the King" in England. 

Mr. Home sent records of WGY for 
November 22, 23, 24 and 25, indicating 
that he has little difficulty in picking up 
the Schenectady station whenever it is 




'gene Mcdonald 

He is owner of the Zenith-Edgewater Beach Hotel Station WJAZ, presi- 
dent of the Chicago Radio Laboratories, president of the Zenith Radio 
Corporation and president of the National Association of Broadcasters. 
He equipped the MacMillan arctic ship with radio receiver and transmitter 
and talks to MacMillan every Wednesday night from the Chicago station. 
On the night of Dec. 19 when talking to MacMillan his voice was heard 
in the Samoan Islands, more than 7,300 miles distant. So far as known 
this is a world record. Mr. McDonald is a hunter, and a yachtsman. He is 
leader of the great fight against the American Society of Composers, Authors 
and Publishers, who tried to force broadcasters to pay large fees for broad- 
casting popular music. His real name is E. F. McDonald, Jr., and it is a 
name that is growing bigger and bigger in radio. (Walinger.) 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 




TIME SIGNALS 
Each day at noon C. J. Waldron, of Medusa, N. Y., gets the time signal 
from Station VVGY, the General Electric station at Schenectady. Right 
on the dot he pulls the rope and rings the village churchbell, thereby afford- 
ing towns folk and farmers with the means of setting clocks and watches. 



on the air. Accompanying the VVGY 
records were log's on reception of English 
broadcasting stations, and it was ob- 
servable that the WGY transmission 
faded less than that of the English sta- 
tions. 

Probably the most interesting long 
distance record made recently by an 
American broadcasting station was that 
of the Zenith-Edgewater Beach station 
VVJAZ. On December 19, or early in 
I he morning of December 20, Eugene 
F. McDonald, Jr., president of the Na- 
tional Association of Broadcasters and 
owner of the famous Chicago station, 
was talking to Donald B. MacMillan, 
ice-locked in his ship near the North 
Pole. United States Naval radio oper- 
ators reported three days later that Mr, 
McDonald's voice had been heard clearly 
in the Samoan Islands, more than 7,300 
miles away. 

Away down there in the South Seas, 
twelve degrees south of equator, the 
operator of a radio receiving set was 
"listening in" for any bits that he might 
pick up from the world abroad. 



Doubtless the Samoan operator was 
interested in the messages that were 
going out to Dr. MacMillan, but, being 
a good radio operator, he must have had 
quite a thrill when he realized that he 
was making a reception record that 
probably surpasses any other achieve- 
ment thus far recorded. 

First news of the remarkable incident 
reached the office of the Zenith Radio 
Corporation at 332 S. Michigan av., when 
the United States Naval Radio Station 
on the Municipal Pier, Chicago, called 
on the telephone and reported they had 
a message from Samoa reading as follows: 

"YMG reports as follows: Please 
inform Zenith-Edgewater Hotel Radio 
Station that Chicago messages and music 
to MacMillan, North Pole, were received 
by meat 7:45, Samoa time, December 10. 
"ROBERTS." 



Medford Hillside, Mass., and Station 
2-LO, London, England, it was a re- 
markable coincidence that the first 
American station to participate success- 
fully in this two-way communication 
was Amrad VVGI, the world's oldest 
broadcasting station operating today, 
erected in 1915. It was a further sig- 
nificant coincidence that Mr. H. f. 
Power, founder and active head of 
Amrad, who conducted the early- 
broadcasting in 1915 and '16 and now- 
known as the "father of broadcasting," 
was at the microphone when the success- 
ful broadcast was made. 

According to the schedule two-way 
communication was not to be tried until 
Saturday, December 1; but when 2-LO 
received the American station November 
30, the British amateurs could not re- 
frain from calling back and were heard 
by many American listeners. 

Again on Saturday two-way com- 
munication was maintained between 
Amrad VVGI and 2-LO London and 
complete confirmation followed after 
an exchange of cablegrams. The achieve- 
ment was all the more remarkable as 
the American station used only 150 watts 
in the antenna. 



WTAM's Record 

The new high powered broadcasting 
station, VVTAM, in Cleveland, Ohio, was 
heard in England before any special 
efforts were made in trans-Atlantic 
broadcasting. 

Mr. Hamblett, from St. Helen's, also 
wrote that he heard the Willard Com- 
pany's station quite clearly broadcast- 
ing its program on Wednesday evening, 
November 2 1. 

He picked up VVTAM at 3:48 a. m., Lon- 
don time which is five hours earlier than 
New York time, and heard the remainder 
of the Willard program with practically 
no interference until the station signed 
off at 4:13 a. m., London time. His 
letter stated that his reception of "The 
Lost Chord" sung by the Amphion Male 
Quartette was almost perfect. Han - 
blett's set is one of his own assemblv. 
using one stage of radio frequency and 
detector tube. His aerial, according 
to his letter consists of a single wire 
antenna 100 feet long and 33 feet high. 

A number of other applause lette s 
have been received from foreign countrie i 
within the two months this station, 
operated by the Willard Storage Batte y 
Company of Cleveland has been on the 
air. 



AMRAD'S RECORD 

When two-way communication by 
voice was established for the first time 
in the history of radio, Friday evening, 
November 30, between Amrad VVGI, 



Two Other Records 

A. F. Combs, of Enid, Okla., and 
M. B. Norman, Eureka Center, Wis., 
reported what are believed to be long- 
distance receiving records for 3-tube 
sets. 

Using receivers of the same type that 
were designed and built by Dr. Fulton 
Cutting and Bowden Washington, 
Minneapolis, Minn., Combs, at Enid, 
listened to three numbers — vocal, or- 
chestra and piano — broadcast by 2-LO, 
London, Eng., and Norman picked up 
a station at Glasgow, Scotland. 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



31 



Combs verified his feat through 2-LO's 
New York office and Dick and Adolph 
Danielson, of St. Croix Falls, Wis., who 
were listening in with Norman. 



SUNSET STATION 

KGO, the Sunset Station, has come 
on the air with the new year. On 
the western edge of the United States, 
at Oakland, California, two steel towers 
have arisen and from the antenna, on 
January 8, the new voice vibrated on the 
air. KGO is the second 
link in a chain of three 
super-broadcasting sta- 
tions planned by the 
General Electric Com- 
pany. The first is WGY, 
at Schenectady, N. Y., 
now completing two 
years of popular broad- 
casting, and the third 
will be erected at Den- 
ver, Colorado. 

For the first time an 
entire building has been 
constructed to house a 
great station and its 
equipment to be used 
exclusively for popular 
broadcasting. This indi- 
cates that the General 
Electric Company has 
faith in the permanence 
of broadcasting. 

The Oakland station 
in its studio, control- 
room and power station 
embodies the latest de- 
velopments in the art. 
Its power and antenna 
systems, a thousand feet 
away from the studio 
building, include all the 
mechanical and techni- 
cal refinements that have 
marked the new achieve- 
ments in broadcasting. 
By means of KGO the 
listener in Maine be- 
comes an air neighbor of 
the folks in California. 

The Pacific Coast sta- 
tion is located on East 
14th Street, Oakland. 
It is a two story brick 
building. On the first 
floor, near the entrance, 
is the office of the studio 
manager who plans pro- 
grams, selects artists, 
and co-ordinates the du- 
ties of the office and broadcasting staff. 

Close at hand is the correspondence 
room where the business of the station 
is carried on. Here a staff of assistants 
attends to the details of program-making, 
interviews callers, keep logs of every 
performance and answers and files the 
letters received from the listeners. 

On this floor there is an attractive 
reception room covered, as is the en- 
trance hall and stairway, with a rich, 
heavy piled carpet of a beaver taupe 
color. The woodwork is painted a soft 
antique ivory and is glazed a VanDyke 
brown. The walls are covered with a 
two tone gray and blue figured tapestry. 
Draperies of blue and taupe damask 



enrich the appearance of the room which 
is furnished with carved walnut furniture 
of the 18th century period. Adjoining 
the reception room is the ladies' rest 
room. On the first floor is also a large 
room for motor generator sets and stor- 
age batteries. 

On the second floor are two studios 
similarly appointed, one large enough 
to accommodate a chorus or symphony 
orchestra; the other, a smaller room, 
for the broadcasting of solos and ad- 
dresses. The use of the two studios also 



NO«~TH POt,E 




7,300 MILES 
Among all the recent distance records recently made by 
radiophone broadcasting stations by far the most startling is that 
of WJAZ, the Zenith Edgewater Beach Station, Chicago. E. F. 
McDonald, Jr., was talking to Dr. Donald B. MacMillan, ice- 
bound near the North Pole and his message was heard by a radio 
operator in the Samoan Islands. The South Sea operator's achiev- 
ement was reported three days later by the U. S. Naval radio 
station at Chicago, having been relayed back by naval operators. 

makes continuous broadcasting possible. 
The announcer has but to step from one 
room to the other at the conclusion of a 
number and find the next performer 
waiting for the word to begin. 

It is in the main studio that the art 
of the decorator reaches its fullest ex- 
pression but before the artist began his 
picture, working with tapestry, carpets 
and draperies, the engineer had lined 
the walls with a mesh of insulated wires 
connecting microphones with control 
apparatus in an adjoining room. After 
the wiring was completed exhaustive 
experiments were made to determine 
the reverberating qualities that the 
proper amount of "damping" might be 



secured to assure maximum musical 
quality. Walls and ceiling were covered 
with special sound-proofing material 
and then the studio was turned over to 
the artist. The decorator has hidden 
all evidences of the true purpose of the 
room. 

Adjoining the st-.dios is a "silent" 
room in which the performer is ushered 
to remain until summoned to the studio. 
On the second floor, but unseen by 
the performers, is the control room. 
Here with headphones at ear, operators 
listen critically to every 
word and note compen- 
sating for differences in 
tone and volume among 
the artists and flashing 
warning through silent 
electric signals to the 
studio manager, when it 
is necessary to alter the 
position of the singer or 
instrumentalist in respect 
to the microphone. The 
control room has three 
stages of speech amplifi- 
cation consisting of two 
5-watt tubes and four 
50-watt tubes. A fourth 
stage of speech ampli- 
fication is installed in the 
power house. 

KGO is operated at 
1000 watts, but the 
equipment is designed in 
excess of that power for 
purposes of conducting 
tests. In operating high- 
powered equipment be- 
low normal rating in 
broadcasting, tubes and 
rectifiers are not subject 
to occasional overloads 
and, as a result, superior 
quality and greater re- 
liability of transmission 
is obtained. 

The power house and 
antenna system are 1000 
feet from the studio 
building. Nine motor- 
generator sets in the 
power house supply fila- 
ment and plate current 
for the oscillator, modu- 
lator and kenotron recti- 
fier tubes. 

There are six tubes in 
the kenotron rectifier 
assembly, one metal 
plate oscillator tube, and 
one metal plate modu- 
lator. Every part of the equipment in 
the power house and in the control room 
is in duplicate, assuring uninterrupted 
service. If one outfit or part of an outfit 
breaks down during the operation period 
another outfit will be ready to be brought 
into the circuit. 

The antenna is of the multiple-tuned 
type and is strung between two steel 
towers, each 150 feet high and 250 feet 
apart. Beneath the antenna is the 
counterpoise consisting of a network 
of wires, fourteen feet above the ground, 
covering an area of 150 by 300 feet. In 
addition to the power house which is 
one story high, 71x32 feet, there is a 
small building for the tuning apparatus 



32 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



and the end of the multiple-tuned 
antenna. 

KGO, the Pacific Coast station of 
the General Electric will not be de- 
pendent upon its own studios alone for 
programs. Located as it is near the 
great cities of the Pacific Coast, it has 
a rich field from which to select music 
and eloquence. By means of broadcast- 
ing pick-up circuits, the Sunset Station 
will be equipped to broadcast the speeches 
of important public gatherings, the ad- 
dresses of prominent citizens, sermons 
by pastors of leading churches, concerts, 
theatre productions and occasionally, 
important athletic events like baseball 
or football games. 

The Oakland station will be on the 
air every Tuesday, Thursday and Satur- 
day nights carrying instruction and enter- 
tainment to the great audience of the 
Pacific Coast and, when atmospheric 
conditions are favorable, to the fans 
throughout the country. The wave- 
length of KGO is 312 meters. 

Martin P. Rice, director of broad- 
casting for the General Electric Company 
has charge of KGO, the new Oakland 



station, WGY at Schenectady and the 
proposed Denver station. J. A. Cran- 
ston, Pacific coast manager for the G-E, 
has direct supervision of KGO. 



Portable Station 

A SHORT wave radio transmitting set 
-^*- which may be transported to the scene 
of church services, concerts, dramatic 
performances or lectures, as easily as a 
motion picture cameraman is sent on 
news- weekly assignments, has been intro- 
duced as part of the broadcasting equip- 
ment of WGY, the Schenectady station 
of the General Electric Company. 

This set is not used to broadcast 
directly to the listener, but is a radio 
relay which conveys the program to the 
broadcasting station. This first radio 
transmission can not be tuned in on the 
average radio receiving set. 

The portable transmitting set is 
conveyed to the hall or church from 
which it is desired to broadcast an enter- 
tainment or sermon. Wire connection is 
established between microphone or pick- 
up within the hall or church and the 




transmitter of the portable set outside. 
The wavelength is too low to interfere 
with the usual receiving sets or broad- 
casting stations and it is also so low that 
there can be no interruption from spark 
transmitters. 

By means of a sensitive receiving set 
located near WGY, the electrical vibra- 
tions into which speech or music has been 
converted are picked up, amplified and 
then conveyed to the main transmitting 
equipment of WGY, from which the 
program is put on the air on the licensed 
wavelength of the station, 380 meters. 

Prior to the introduction of the radio 
relay it was customary for WGY to con- 
nect church and radio station by wires. 
Wire installations required considerable 
preparatory work and because of the 
time involved in making the necessary 
installations some programs that might 
have proved instructive and enjoyable 
had to be omitted. The small trans- 
mitting set is mounted in a covered 
truck and may be taken to hall, theatre or 
church, where in a short time the installa- 
tion will be complete and ready for 
service. 

Re-broadcasting does not affect the 
quality of music or speech. WGY has 
made frequent use of the radio relay 
methods and the listeners were at no 
time aware that a radio transmitting 
set working on a low wavelength had 
supplanted the wire link in the system. 

There is another and even more im- 
portant use for the small transmitting 
set in radio relay and this use suggests a 
particularly interesting development for 
radio in the future. 

In the relay now in common use at 
WGY, the small station is used to feed 
into the larger transmitting set through 
the introduction of a receiving set 
between the radio links. It is possible 
that the future will see many of these 
small transmitting sets scattered about 
the country and used to re-radiate on 
lower wavelengths, concerts received on a 
sensitive receiver from any one of a half 
dozen main stations, for the benefit of 
listeners with crystal sets or short dis- 
tance receivers. 

For example, such a receiving set might 
pick up the best of the WGY program 
from Schenectady and then a special 
feature from WJZ or other station and 
by the use of the transmitter re-radiate 
to the country side within a limited dis- 
tance of the station. 

This would give the man with the 
small receiving set the advantage of 
listening to a selected program, the best 
of the main stations. In this manner he 
would be able to get programs, and to 
get music that would not otherwise be 
available to him on his set. Many of I he 
distant stations can be tuned in at will 
when atmospheric conditions are right 
but there are nights and days when the 
average set has difficulty in getting dis- 
tance. The small re-radiating or relay 
station practically assures success to all 
the fans within a hundred miles, at least. 



RIPPING! 

That's what the Duke of Sutherland thinks about radio. He has been 
investigating American aviation and the picture shows him talking to 
American BCL's from Station WJZ, New York. Swagger microphone and 
topping haircut, we say. (Kadel & Herbert.) 



Radio in Jail 

"Four walls do not a prison make — 
nor iron bars a cage." The line from the 
old poem has been applied to many situa- 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



33 




RADIO PENETRATES STEEL TUNNEL CASING 
G. Y. Allen, radio engineer of the Westinghouse Manufacturing and Electric Company is shown testing recep- 
tion conditions in the New York-New Jersey vehicle tunnel. Broadcasting was distinctly heard from Philadelphia, 
Pittsburgh and other cities. The radio waves passed through 500 miles of air, 70 feet of water, 30 feet of mud and 
through the heavy steel casing of the tunnel. (Photonews.) 



tions since it was written. Now comes 
its application to radio. 

WTAM, the broadcasting station of 
the Willard Storage Battery Company, 
Cleveland, Ohio, received Christmas 
greetings from three prisoners in ac- 
knowledgment of radio programs re- 
ceived by them. Two of these were pris- 
oners of sickness. The third is actually 
confined in a state prison. 

Mrs. Harold N. Pember, of 14 Goshen 
Street, Hartford, Conn., sent a disin- 
fected letter, saying she was quarantined 
with her daughter who has scarlet fever. 
"You will never realize what a boon the 
radio has been on these long, lonely 
evenings," she wrote in appreciation of 
WTAM programs. 

Robert H. Bean, of Manitowoc, Wis., 
sent the season's greetings, saying there 
is no station in the United States he en- 
joys more than WTAM. Bean was a 
marine engineer on the Great Lakes be- 
fore an accident left him paralyzed. 
Cleveland, the home of WTAM, is fa- 
miliar ground, he says, and the concerts 
bring back the good times he has had in 
port there. 

The third letter was from Ernest 
Graham, prisoner in Virginia state peni- 
tentiary, Richmond. 

Graham is allowed a radio receiving set 
in his cell through the kindness of the 
prison superintendent. He says there are 
twenty-four head phones attached to his 



receiver and that his companions in near- 
by cells listen in to concerts after the 
lights are out. 

"The radio helps us to pass the long 
nights as well as to keep up our courage 
and to appreciate what freedom means 
once we get it again," he writes. 

"BIG BROTHER CLUB" 

Boy and girl radio fans all over the 
East are becoming greatly interested 
in the newest Amrad broadcasting 
feature conducted at WGI, Medford 
Hillside, under the name of "The Big 
Brother Club." Over 200 boys and 
girls are enrolled as active members at 
the present time. 

"The Big Brother Club" is not unlike 
the Boy Scouts and Camp Fire Girls 
in purpose and principle. It appeals to 
boys and girls from 9 to 12 years old, 
and, according to the by-laws, "any 
boy or girl owning or listening-in regularly 
on any receiving set is eligible." The 
dues are one letter each week to "Big 
Brother." Meetings held nightly from 
6 to 6:15. Each new member is issued 
a Certificate of Membership Card duly 
inscribed. 

It is expected that Big Brother Clubs 
will be established at other broadcasting 
stations in the near future. Address 
all communications to C. R. Emery, 
care of Amrad, WGI, Medford Hillside, 
Mass. 



"Mike" Tests Nerves 

Broadcasting has developed a new test 
for the nerves, according to several radio 
broadcast managers. 

"Stage fright," "movie nerves" and 
"buck fever" are all well known to the 
public, but the little metal microphone, 
"the door to Radio land," has sent terror 
to the hearts of many seasoned enter- 
tainers who have performed before 
packed houses without a tremor. 

Appearing for the first time before the 
"Mike" the artists, almost without ex- 
ception, ask: "How many people will 
hear this?" What tone of voice shall I 
use? Do you think I have a good voice 
for this work?" and many other ques- 
tions indicating nervousness. 

Having performed before "Mike," 
who is cold and unresponsive, the artist 
waits impatiently for letters from the 
invisible fans, whose faces he could not 
read, to learn whether or not his act 
"went over." Unless he receives letters 
of applause his fever is likely to rise 
until it becomes dangerous. 




RADIO AGE— "THE MAGAZINE OF THE HOUR" 




DIAL TWISTERS 

Names Addresses Circuit 

Norris Summers Pee Wee Valley, Ky Single Circuit 

Richard Jones Milwaukee, Wis.._ Single Circuit 

Earle Kidney Sterling, 111 Single Circuit 

Harvey J. Duneka 2641 N. Central Ave., Phoenix, Ariz.. Ultra Audion 

Curtis Springer 1224 N. Olney St.._ Single Circuit 

Kenneth Fischer... 1219 N. Olney St.._ Single Circuit 

Both the above TWISTERS live in Indianapolis, Ind. 

John Bennett Rockville Centre, L. I., N. Y Not Stated 

Albenue Des Rosius.... 56 Bridge Av., Windsor, Ont., Can Reinartz 

Alex Mack 1020 Cherry St., Norristown, Pa Hopwood Circuit 



ONCE upon a time there was an 
Editor who wanted to give the 
fans a chance to compare records 
in his radio magazine and let the readers 
know that he wanted lists — 

That's us. We like to give the fans 
what they want, and we try to please 
them in every way possible 

Some time ago, we requested through 
this department that fans send in their 
lists of stations heard, and we got just 
what we deserved. No restrictions were 
published as to the length of the lists, 
and by looking over some of those sub- 
mitted, you'd think you got a hold of the 
call book for all the stations of the world. 

We find that it is an impossible thing 
for us to determine the record holder for 
the month, and we cannot find any real 
restrictions to impose on these fans who 
laugh at distance as far as radio listening 
is concerned. 

It's this way. Willie Jones writes in 
telling us that he has heard station 
XYZ transmitting on sixteen meters, 
which is located four thousand miles 
from his house. Mr. Smith tells us that 
his set using a 23-tube ultra-super- 
heterodyne has heard all in all six hun- 
dred stations from the Alps to Omaha. 

The point is — whose should be con- 
sidered a record? 

We'll handle it this way. In order to 
give all the fellows a chance at this, we're 
going to establish the order of DIAL 
TWISTERS. We'll publish the lists of 
those fellows who do real long distance 
work from a standpoint of location, type 
of set, and operating conditions. When 
you write enclose your list neatly com- 
piled, with data on the type of receiver, 
and any other information that you think 
would be of value in determining whether 
you are entitled to the name of DIAL 
TWISTER. 

The Pickups editor will read them 
over carefully, note the lists, and condi- 
tions under which the work was done, and 
if he thinks it contains something of a 



feat, will put your name in the list of 
DIAL TWISTERS, and if space permits 
publish your letter. 

Everybody has an even chance — no 
matter if you have a ten-tube super- 
heterodyne or a one-tube first tube cir- 
cuit. We will carefully consider them 
both, and if the one list and letter shows 
more meritorious work, we will publish 
that one. 

What say fans! How many of you are 
going to be classed as dial twisters next 
month? 

THE PICKUPS EDITOR. 



Our December 1923 issue contained 
an interesting account of reception 
record made by Mr. E. L. Laudell, of 
Shelbyville, Illinois on a circuit of his 
own design. Mr. Laudell instructed us 



to say that fans could have a copy of his 
circuit by writing. In a later communi- 
cation, Mr. Laudell says: 

"I throw up my hands — I can't possi- 
bly answer the mass of inquiries that 
come in. While I am writing this, I 
have a splitting headache from writing 
and reading letters in answer to inquiries 
received in response to the offer I made. 
I have now received 500 letters." 

We wrote Mr. Laudell for his circuit, 
and in reply he says: 
RADIO AGE, 
Gentlemen: 

You will find enclosed the circuit on 
which I compiled the list of stations pub- 
lished in your December, 1923, issue. 

Upon inspection you will see that the 
circuit needs no comment or special 
parts other than a common variocoupler 
which must be rewound to suit the cir- 
cuit given. I am enclosing detailed infor- 
mation regarding the winding of the coils 
on this coupler, and trust that fans may 
find as good results awaiting them as I 
have received. 

Very truly yours, 

E. L. LAUDELL. 

We are printing in Figure 1, a copy of 
the circuit which Mr. Laudell contends is 
superior to many others. The primary of 
the coupler has eighty turns of No. 28 
D C C wire, with taps taken off as fol- 
lows: 




Adjustable 



UGRN16R 



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RADIO AGE— "THE MAGAZINE OF THE HOUR" 



35 



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Hol cent, per word per insertion, in advance. Name 
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If you have not bought your Remarts Book, fully 
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RADIO ODDS AND ENDS 
No. 14 square tinned bus wire — ■ 2 ft. lengths — 64 feet 
for $1.00. $1.20 set of 8 lettered binding posts— 60c. 
Spaghetti — 3 ft. lengths, red, yellow, green or black — 
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return mail — $3.00. Radio list for stamp — none free. 
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Tap the first ten turns every turn, and 
then wind seventy turns of the wire 
bringing out loops for taps every tenth 
turn. This makes the coil have seven 
taps of ten turns each and ten turns of 1 
tap each. The secondary is rewound 
with the same size wire and had 64 
turns. The secondary in the circuit 
really is not a secondary but is used as a 
tickler. 

The remainder of the circuit is standard 
with respect to parts, and the diagram 
shows how the connections are made. 
Mr. Laudell would be pleased to hear 
from fans who construct this circuit. 



On page 4 of the August issue, we print- 
ed a short item regarding reception of 
signals on short antennas by various 
fans, and Mr. B. O. Borgeson found that 
a score of people took the trouble to look 
up his address, and write him concerning 
his experiments. 



Mr. Norris, Summers, Pinvee Valley, 
Ky., writes us: 
RADIO AGE, 
Gentlemen: 

After reading Mr. Foltz's letter in the 
January number last night I decided to 
take down the stations heard before 
turning in. 

So as a result I am sending my list 
which contains fifty stations all of which 
were plain and clear. 

I do not claim this to be a record as I 
can easily do as well any good night. 
My set is a single tube type, using a 
U V 199, in the much ridiculed single 
circuit. 

Very truly yours, 
NORRIS SUMMERS. 

Mr. Summers' list is as follows: 
CKAC, Montreal, Can.; WJAR, Provi- 
dence, R. I.; WOAW, Omaha, Neb.; 
WCAE, Pittsburgh, Pa.; WWJ, Detroit, 
Mich.; WOR, Newark . N. J.; WHAM, 
Rochester, N. Y.; WHAS, Louisville, 
Ky.; WDAP, Chicago, 111.; WGY, 
Schenectady, N. Y.; WDAF, Kansas 
City, Mo.; WJAX, Cleveland, Ohio; 
KFKQ, Conway, Ark.; WCX, Detroit, 
Mich.; WTAS, Elgin, 111.; WSAI, Cin- 
cinnati, Ohio; WBZ, Springfield, Mass.; 
WSB, Atlanta, Ga.; WMC, Memphis, 
Tenn.; KSD, St. Louis, Mo.; KYW, 
Chicago, 111.; WIP, Philadelphia, Pa.; 
KDKA, Pittsburgh, Pa.; WEAF, New 
York, N. Y.; WFAA, Dallas, Texas; 
WJAD, Waco, Texas; WNAC, Boston, 
Mass.; WEAN, Providence, R. I.; 
WCAP, Washington, D. C; WMAK, 
Lockport, N. Y.; WCAS, Minneapolis, 
Minn.; WOAN, Lawrenceburg, Tenn.; 
WLAP, Louisville, Ky.; WHN, New 
York, N. Y.; WOI, Ames, Iowa; WHB, 
Kansas City, Mo.; WJZ, New York, 
N. Y.; WBAP, Fort Worth, Texas; 
KFMQ, Fayetteville, Ark.; KFEX, Min- 
neapolis, Minn.; KGO, Oakland, Calif.; 
KHJ, Los Angeles, Calif.; WJAZ, Chica- 
go, 111.; WLW, Cincinnati, Ohio; WBAK, 
Harrisburg, Pa.; KPO, San Francisco, 
Calif.; KFI, Los Angeles, Calif.; WJAN, 
Peoria, 111.; KFDL, Denver, Colo.; 
KGW, Portland, Oregon. 

Wot say, fans? Looks like the single 
circuits are coming to the front this 
issue. Wc remember way back when a 



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36 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



Pickups By Readers 



fellow could look with pride at a record 
of thirty miles or so with an electrolytic 
detector — and now 

Read this one and weep! 
RADIO AGE, 
Gentlemen: 

I have read with interest letters in the 
Pickups Dept. Now I'm out with my 
record, which I believe takes honors 
from Mr. Foltz in the January number, 
and also Mr. Wright of Madison, Wis., 
in the same issue. I have a single tube 
single circuit receiver which I built 
myself and wouldn't trade it for any set 
regardless of make or price. I have 
heard 151 stations in thirty-two states. 
The following are stations over 1000 
miles distance: KPO, KFDB, KFI, 
KWH, KHJ, PWX, CHBC, CFCN, 
WCAR, WCAK, WBAP, WPA, WFAA, 
KFDF, KFAF, WWL, WAAP, WFY, 
WEAH, WBL, WKY, KFKB. 

A total of twenty-two stations with a 
32,650 mileage. If any other reader can 
show twenty-two stations totaling that 
much with a single tube set, I would like 
to see it. I have heard as high as thirty- 
three stations in a single evening between 
seven thirty and eleven thirty. In three 
nights I heard 51 different stations and 
did not count any station twice either. 

Here's another: I have listened to 
KFI at Los Angeles four consecutive 
nights for from 30 to 45 minutes each 
time. Perhaps I could have listened 
longer only the lure for more distant 
stations would not permit me. 

I owe all my success to a good tube, 
and careful tuning. 

Yours for RADIO AGE, and single 
circuits, 

RICHARD JONES. 

When you read over that, you'll 
probably say Ummm! Pretty good, 
pretty good, but we'll say — GOOD!!! 
HUH! THAT'S PERFECT! We think 
it's so good that we're putting Mr. 
Jones' name on the Dial Twisters list. 
Congratulations, Mr. Jones. You're 
one of the highest Dial Twisters for the 
month. 



And here's another single circuit bug: 
RADIO AGE, 
Gentlemen: 

I have been reading some of the fine 
distance records made by fans, and want 
to contribute my list. I am using a 
single circuit tuner, and for selectivity 
and ease of control together with its 
great volume I don't believe it can be 
beat. I can't just remember the date but 
a week or two before Christmas I picked 
up the following stations from seven in the 
evening to ten: KYW, Chicago (West- 
inghouse Elec.) : WOAW, Omaha; WLAG, 
Minneapolis; KDKA, East Pittsburgh; 
WGY, Schenectady; WLW, Cincinnati; 
WDAP, Chicago (Drake Hotel); WJAX 
Cleveland; WJY, New York City; 
WDAF, Kansas City Star; WCAE, 
Pittsburgh; WMAQ, Chicago (Chi. Daily 
News); WBAP, Ft. Worth; WJZ, New 
York City; WHAS, Louisville; WOAI, 
San Antonio; WBZ, Springfield, Mass.; 



(Continued) 

WOC, Davenport; WSB, Atlanta; WHB, 
Kansas City; WWJ, Detroit News; 
WTAS, Elgin; WSAI, Cincinnati; WRM, 
Urbana, 111.; WEAF, New York City; 
WFAA, Dallas; WCAP, Washington, 
D. C; WBAH, Minneapolis; KSD, 
St. Louis; KFKX, Hastings, Nebr.; 
WNAV, Knoxville, Tenn.; Washington, 
Pa.; KHJ, Los Angeles, Calif.; CKY, 
Winnipeg, Canada; WJAZ, Chicago 
(Edg. Beach Hotel). 

KHJ, KFI and CFCA and other Pa- 
cific stations all come in with surprising 
volume and clearness. I can pick them 
up when they are on the air at will. 
Last Saturday evening (January 12) I 
heard about twenty-three stations and 
not trying for records either. In the 
course of the evening I had heard among 
others PWX, KGO, KHJ, KFI, KGW, 
CKCE, WHN and KPO. Pretty good 
jaunt, don't you think? Local stations 
such as Chicago and Kansas City come 
in so loud that you can hear them 15 to 
20 feet from the phones. 

Let me hear from some other single 
circuit fans as to a record of stations 
heard as consistently as that! 
Very truly yours, 

EARLE KIDNEY. 

Sterling, 111. 



The copy boy watching over our 
shoulder as we type this remarked with a 
whistle: "Whew! I'm gonna' go home 
t'nite an make me one of them tuners. 
Wotta list, wotta list." We're almost 
ready to follow the copy boy's example 
and junk that Rolls-Royce receiver of 
ours after reading that list. Fine work, 
Mr. Kidney. 



Dec. 31, 1923. 
RADIO AGE, 
Dear Sirs: 

I have been greatly interested by what 
RADIO AGE has to say on the Ultra 
Audion Circuit. For the past eight or 
ten years I have been trying the various 
hook-ups as fast as they have been 
foisted upon the unsuspecting experi- 
menter, but even the ones with lots and 
lots of dials and switches can't beat the 
Ultra Audion for volume or selectivity. 

At present I have only the 23 plate 
variable condenser, and a rheostat, on the 
panel, with 75 turns of No. 24 wire on a 
Quaker Oats box in the rear as a fixed 
inductance — no taps. I find this far 
superior to the other methods of winding 
coils; the variable condenser covers 
meters from 238 to 526 with a 75 foot 
aerial, and tuning is very sharp. Using 
one tube I regularly hear Chicago from 
Phoenix, Ariz., with KFAD, a mile 
away, making all the noise he can. 

In thanking you in advance, I would 
like to add that RADIO AGE is exactly 
right — please, for everybody's sake, don't 
let it slide into the rut. 

Sincerely yours, 
HARVEY J. DUNEKA, 
2641 North Central Avenue, 

Phoenix, Arizona. 



That's a little boost for the users of 
ultra-Audion receivers and here's another 
one: 

RADIO AGE, 
Gentlemen: 

As a radio amateur of long standing, 
but who has only lately become ac- 
quainted with RADIO AGE, permit me 
to felicitate you upon the practical wis- 
dom and sound judgment which its 
editorial contents show. 

I read four different radio periodicals. 
Each is good of its kind. Yours is 
quite the most useful to the everyday 
semi-dumbbell like myself, who wouldn't 
know a heterodyne if it bit him on the 
ear, but who does admire for to fool away 
life building new circuits for his ownself. 

Incidentially, even for those of a high- 
er order of mentality than mine, I ob- 
serve a definite authority and precision 
in your published utterances which are 
a pleasing contrast to the wide scope 
many radio editors seem called upon to 
allow themselves. 

I specially congratulate your Mr. 
Felix Anderson upon the clarity and 
accuracy of his drawing. Nothing more 
helpful to me has come my way since 
first I dealt with radio. 

I built the ultra-audion one tube cir- 
cuit, described in your October number, 
from one of Anderson's drawings; and 
it is a marvel of compactness and effici- 
ency. It outclasses a sixty-dollar 
"boughten" set in distance and selectiv- 
ity, as well as in volume and freedom 
from distortion; while, as you can guess, 
it didn't cost anything like that money! 
May I suggest the addition of a vernier 
condenser similar to the Chelten Midget, 
which I am using in this circuit of yours 
and which I find a great help in cutting 
out interference. 

The first night I hooked up the set 
I got QSADX on the following: CHYC; 
WIP; WDAR; WSAI; WEAF; WOC; 
WOO; and the rarely-heard (by me, at 
least) WOQ. These, in the order named, 
within an hour and a half, tuning through 
local broadcast from WWAP on 225 
meters. Not so dusty, what? 

Good luck to you! 

Yours sincerely, 

D. G. WYLIE. 



And seeing that we are featuring 
single circuit sets this month, we give 
you a shot at this one compiled by two 
youngsters in the radio game: 
RADIO AGE, 
Gentlemen: 

We have read several copies of your 
magazine. We have taken special in- 
terest in the "pickups." We are the 
proud jowners of a single circuit regen- 
erative one-bulb set. We have a record 
which was made on the 11th of January, 
1924, and we think this record cannot 
be equalled with such a set. We listen- 
ed between the hours of 6 p. m. and 3 
a. m. They are as follows: AA3, 
KDKA, KFGC, KFI, KFKX, KFMQ, 
KGW, KHJ, KYW, WBAK, WBAP, 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



37 



WBAV, WBZ, WCAE, WCBD, WCK, 
VVDAF, WDAP WDAR, WEAA, 
WEAY, WGY, WHAS, WHB, WHN, 
WIAO, WIP, WJAR, WJAZ, WMAH, 
WMAQ, WMC, WOAW, WOO, WOQ, 
WOS, WSB, WTAQ, WWJ, 3FA, 9BAC, 
9BAQ, 9VC, WLW, WOC, WLAG, 
KFBC. 

We also got a Canadian steamer, the 
Memphis. We are a couple of radio 
nuts of 14 years. In ten months we 
have received 276 stations all different. 
We have received stations in thirty-four 
states, District of Columbia, six Provinces 
of Canada, Alaska, Cuba, and Porto 
Rico. Tne night we got Alaska we 
were using three bulbs. We are positive 
we heard all of these stations for our both 
ears would not deceive us. 
Yours very truly, 

CURTIS SPRINGER, 

1224 N. Olney St. 

KENNETH FISCHER, 

1219 N. Olney St., 
Indianapolis, Ind. 



And here's another list from a radio 
bug not yet in his teens which surpasses 
some of the lists we have received from 
fellows who are twice his age and who 
have more than twice his radio experi- 
ence: 

I have seen quite a few records in the 
RADIO AGE and I think mine will 
beat them all. I have heard the follow- 
ing: KDKA, KYW, KHJ, KSD, 
WAAM, WBAA, WBAN, WBAP, WBS, 
WBZ, WCAU, WCX, WDAP, WDAR, 
WEAF, WEAN, WFI, WGI, WGR, 
WGY, WHAS, WHAZ, WHB, WHN, 
WIP, WJAR, WJAZ, WJZ, WLAG, 
WLAK, WLAW, WLW, WMAK, 
WMAQ, WNAC, WOC, WOO, WOR, 
WPAB, WQAO, WRW, WSB, WWJ, 
WMAF, WBAY, NAA, WJY, WSAI, 
WCAP, WCBD, WCAE, WRC, WDT, 
WNJ,WTAM, WEAM, WBT, WHAM, 
WCAO, WJAX, WBU, WTAS, WHAR, 
WOAW, WFAA, WDAF, WCAL, 
WNAV, KOP, CFCA, CKAC, 6KW. 

I have heard a few stations that don't 
broadcast any more. I have heard 
eight amateur stations. 

I am only twelve years old and I have 
a list of ninety-three stations in the last 
five months. 

Yours truly, 
JOHN BENNETT, 

Rockville Centre, Long Island, N. Y. 

P. S. — Will you please publish my list? 



Laugh those two off, willya! And 
while you are laughing read this one: 
RADIO AGE, 
Gentlemen: 

I think I have another good record of 
pickups for a two nights' try. I sent 
you a list some time ago, but this one 
has it beat a mile. I am a regular 
radio bug, and use a Reinartz three tube 
set with loudspeaker. Let's get this list 
off our chest right away: KDKA, KHJ, 
KSD, KYW, KFKB, KFKX, WBAP, 
WBAV, WBZ, WCAE, WCAL, WCAP, 
WCBD, WCK, WDAF, WDAP, WDAR, 
WDAX, WEAF, WFAA, WFI, WGR, 
WGY, WHAS, WGR, WHAZ, WHB, 
WHK, WIP, WJAR, WJAX, WJAZ, 
WJZ, WLAG, WMAQ, WMC, WOAW, 
WOC, WOO, WOS, WPAH, WRC, 



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High Grade Cabinet $2.00 

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This is the sensational hookup described in January Radio Age. Everybody 

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38 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



Pickups By Readers 

(Continued from page 37.) 
WSAI, WSB, WSI, WSY, WTAM, 
WTAS, PWX, WCX, WWJ, KOP, and 
amateur stations 8WX, 8MR, 8CAX, 
8IM, and 9XN. 

Well, folks, how about that list? It's 
about time I have a little sleep now so 
guess I'll quit bothering you; but I want 
to say this — your magazine is a wonder. 

I do not miss it any month, as I like 
it the best of them all. It gets better 
every month. The only trouble is that 
you don't get it out often enough. The 
list I submitted was all brought in on a 
loud speaker — no ear phones at all. 
Very truly yours, 
ALBENUE DES ROSIUS, 
256 Bridge Av., Windsor, Ontario, Can. 



Write that one on your cuff! Next: 
RADIO AGE, 
Gentlemen: 

I enjoy very much reading the pickup 
columns and would like to have a few 
of my records appear in your interesting 
publication. I am using a Hopwood 
circuit with detector and two stages of 
amplification employing WD 12 tubes. 
Although situated only 17 miles from 
Philadelphia with WDAR, WOO, WP 
and WFI going full blast, I have tuned 
around them almost at will. My crown- 
ing achievements and the ones of which 
I am most proud are as follows: 

The tuning of stations WHB, WHAS, 
WLAG, SWB, WTAM and numerous 
stations close by using a three foot loop 
for an antenna. 

The tuning of KFI, KHJ, KGW, and 
one morning I tuned in KFI, KHJ, and 
KGW between 12:30 and 1:30. 

On the night of Dec. 28 I tuned in 43 
stations from 7 p. m. to 12:45 a. m. 
(when I fell asleep at the switch). You 
will find the list attached. I also have 
a record of seventeen stations in three- 
quarters of an hour to which my better 
half acted as witness. Although "hear- 
ing is believing" I pride myself on the 
fact that before I log a station I always 
make sure of the call letters or verify 
the reception by reference to some pro- 
gram as published in newspaper pro- 
grams with respect to programs. I sub- 
mit a sample of my log. 

I am a red hot radio fan and could 
write about it forever if I had the time 
but I will close hoping that I have not 
bored you to distraction. 

Sincerely yours, 

ALEX MACK. 
1020 Cherry St., Norristown, Pa. 
A Copy of Mr. Mack's Log Sta- 
tions Tuned in on Dec. 28, 1923: 

KOP, Detroit, Mich., police reports 
and orchestra. 

KDKA, E. Pittsburgh, Pa., dinner 
music. 

WCAU, Philadelphia, Hotel Pennsyl- 
vania orchestra. 

WIP, Philadelphia, orchestra. 

WFI, Philadelphia, orchestra. 

WOR, Newark, bedtime stories. 

WCX, Detroit, orchestra. 

WCAE, Pittsburgh, orchestra. 

WWJ, Detroit, Detroit News orchestra. 

WEAF, New York, artists' concert. 

WOO, Philadelphia, orchestra. 



WGY, Schnectady, orchestra. 

WNAC, Boston, artists' recital from 
WNAC. 

WEAN, Providence, artists' recital 
from WNAC. 

WTAS, Elgin, 111., orchestra. 

WHAM, Rochester, N. Y., reading. 

WMAY, St. Louis, address on church 
work. 

WHK, Cleveland, solos and orchestra. 

WRAX, Gloucester, N. J., soprana 
solo, "Annie Laurie." 

WCBD, Zion 111., xylophone and 
violin solos. 

WJAR, Providence, R. I., orchestra. 

WDAR, Philadelphia, Pa., Howard 
Lannins' orchestra and "Morning 
Glories." 

WHN, New York, orchestra. 

WHAS, Louisville, Ky., time signal. 

WSB, Atlanta, Ga., address on A. 
R. R. L. 

NAA, Arlington, Va., weather report. 

WDAF, Kansas City, concert. 

WJZ, New York, artists' concert. 

WIS, Jefferson City, Mo., Missouri 
state prison band. 

WRC, Washington, D. C, U. S. army 
band. 

WFAA, Dallas, Tex., concert. 

WOAW, Omaha, Neb., orchestra. 

KYW, Chicago, Mary Garden in opera, 
Cleopatra. 

KSD, St. Louis, chorus. 

WBAP, Ft. Worth, Tex., Masonic 
orchestra. 

WJY, New York, soprano solos. 

3AYZ, Philadelphia, testing a new 
transmitter. 

WBZ, Shringfield, Mass., orchestra. 

WDAP, Chicago, songs and market 
reports. 

KFKB, Milford, Kans., orchestra. 

WMC, Memphis, Tenn., late frolic. 

2XB, New York, testing new trans- 
mitter. 

WJAZ, Chicago, quartet and concert. 

Forty-three stations in fifteen states. 

Total mileage, 18,501. 

Time, 7 p. m. to 12:45 a. m. 



The Pickups Editor wishes to ac- 
knowledge receipt of letters from the fol- 
lowing readers: 

H. J. Boyenga, Paul Baker, C. H. 
Peters, R. S. Merchant, B. P. Kes- 
singer, P. Spencer, C. M. Bullard, H. 
W. Dillon, J. J. Drechsler, Max M. 
Barnhizer, Rev. R. A. Brook, and Drew 
D. Mac Dougal. 



Rejectors 

(Continued from page 13.) 
rub comes in) and considerable patience 
will have to be exercised in winding a coil 
of 2,500 turns with so fine a wire as No. 
34. It is possible that you may find coils 
of the dimensions given in some stores 
which handle transmitting apparatus. 

The coil consists of the wire as men- 
tioned 'above, wound on a tube three 
inches in diameter. This coil has the 
property of keeping the interference free 
oscillations which we have just tuned in, 
lrom straying off in the wrong direction, 
and steers them down the antenna post 
of the receiver instead. The coil is an 
absolute necessity in the unit. 

The potentiometer, omnipotent in 



radio frequency circuits, should be of 
about 400 ohms maximum resistance, and 
is used to control the bias of the grid of 
the tube. 

The filament posts of the unit may be 
connected to the common storage battery 
used for the remainder of the set. It is 
advisable if possible to use a separate 
B battery, connecting it to the specified 
posts, but if no additional batteries are 
available the voltage used on the remain- 
der of the set may be applied. The voltage 
should be determined by the type of tube 
used, but as a general rule, about 80 
volts is efficient. 

Those contemplating the construction 
of this type of rejector should carefully 
observe the rule that good results are the 
fruits of painstaking care in construction, 
and discriminating choice of efficient ap- 
paratus. 

The writer wishes to take this oppor- 
tunity to thank Mr. Frederick A. Smith, 
Editor of RADIO AGE, Mr. E. F. McDon- 
ald, Jr., of Station WJAZ for their ef- 
forts in bringing the writer's article in the 
January issue of RADIO AGE before the 
many fans, and wishes to acknowledge 
receipt of the many letters written him 
by grateful listeners in response to the re- 
sults obtained from the instructions 
printed in that issue. 



Simple Heterodyne 

(Continued from page 8.) 
is supplied to the plate of the tube and is 
fed back to the grid circuit through the 
two inductively coupled coils (N) and 
(M). The primary carrying the plate 
current is (N) while the secondary in the 
grid circuit is (M). The primary (N) 
contains about 60 turns of No. 26 D. C. 
C. wire while (M) has about twenty 
turns of the same size wire. In this way 
the plate current frequency is imposed 
upon the grid circuit, and the intensity 
of the energy can be controlled by the 
plate inductance or by varying the dis- 
tance or coupling between the two coils, 
or both. The coil (M) should preferably 
be the. rotor of a coupler while (N) is 
the stator. 

Next to the plate of the tube is the in- 
ductance (L) which may be a 50 turn 
honeycomb coil. Connected across this 
coil is the 23 plate variable condenser 
(C2) by which the inductance is varied 
and by which the frequency in coil (N) 
is varied. This arrangement can be 
somewhat simplified by omitting the 
coil (L) and connecting the condenser 
(C2) directly across the ends of the coil 
(N). ' Coil (N) is now made a 50 turn 
honeycomb. However, the results ob- 
tained by this method are seldom as 
good as in the complete circuit shown. 

Further increase in signal strength 
is due to "tuned plate" methods, the in- 
ductance (L) and Condenser (C2) bring- 
ing the plate circuit into or near to a 
state of resonance in regard to the grid 
circuit. The total result of all these 
systems is a circuit having excellent 
range and terrific signal strength on local 
broadcasting stations. The combined 
adjustment of condensers (CI) and (C2) 
give excellent selectivity and broadcast- 
ing stations only a few blocks away are 
completely eliminated when desired. I 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



39 



have repeatedly cut out the powerful 
station WJAZ only two blocks from my 
home and have brought in out of town 
stations without a trace of WJAZ even 
during silent periods. 

As the tuning of these units is very 
critical at all times it is advised that 
vernier condensers and vernier rheostats 
be used. Condenser (C2) is particularly 
critical and requires very close adjust- 
ment for maximum results. Both these 
variable condensers have a maximum 
capacity of 0.0005 m. f. Trouble with 
body capacity will be in evidence unless 
care is taken to connect the stationary 
plates of condenser (CI) to the grid cir- 
cuit. If the movable plates are con- 
nected at the end of the grid condenser 
(Kl) then the extended shaft of the con- 
denser is at grid potential and every 
movement of the hand on this dial will 
detune the circuit. When an amplify- 
ing tube such as the UV-201A or C-301A 
is used the grid condenser (Kl) should 
have a capacity of 0.00025 m. f. The 
instructions for other tubes will be 
found within the box. 

As a rule, an amplifying tube is better 
than a soft detector tube for this purpose, 
and with the UV-201A a "B" battery 
potential of 67 volts is very satisfactory. 
This makes the tuning sharper and brings 
in distance much better than with the 
ordinary soft detector tube working with 
22.5 volts on the plate. However, de- 
tector tubes can be used if the plate 
voltage is kept down below 25 volts. 
The resistance of the rheostat (R) de- 
pends upon the make of the tube. 

While a variometer can be substituted 
for the inductance (L), yet it will not 
perform so satisfactorily unless a fixed 
condenser of 0.00025 is connected across 
the terminals of the variometer. The 
variometer only adds to the expense of 
construction and in my opinion should 
not be used. Besides, it is likely to in- 
crease the body capacity and cannot 
easily be adjusted with vernier precision. 

Sharp tuning and the other desirable 
characteristics of this circuit will be lost 
if a very long aerial is used. In no case 
should an outdoor aerial of more than 
75 feet be used and 50 feet span is pref- 
erable, particularly if within a few miles 
of a broadcasting station. On 30 feet 
of indoor aerial I have had nearly all 
the stations on one tube, that is, the 
large broadcasting stations usually listed 
in the "pickups" column. With this 
short aerial, the set tunes sharply and is 
very selective over a range of from 200 
to 600 meters wave length. The two 
controls are very easily handled after a 
little practice, and as a fixed type coupler 
is used, the dial of condenser (CI) can 
be logged for the different wave lengths 
and stations. Each station, when ac- 
curately on its assigned wave length, 
comes in sharply each time within one or 
two divisions on a four inch dial. 

A variocoupler can be substituted for 
the fixed coupler shown but it is not 
desirable from any point of view. In the 
first place the number of controls are 
increased, and secondly it is then impos- 
sible to log the stations according to 
wave length. The variocoupler taps and 
inductance switches add to the losses 
in the circuit and of course this is to be 



avoided. The simplest and most effec- 
tive coupler is the one shown here. The 
primary coil (P) consists of about 15 
turns of No. 26 or No. 24 D. C. C. mag- 
net wire, and is wound on a three inch 
cardboard or bakelite tube. The secondary 
coil (S) consists of from 60 to 70 turns of 
the same wire and is wound on the same 
tube spaced about 5-8 inch from the end 
of the primary coil (P). Do not place 
the coils closer together than this for 
the 5-8 inch of loose coupling must be 
provided to obtain selectivity and to 
avoid capacity coupling between the 
two coils. 

The isometric view of Fig. 6 shows the 
typical arrangement of- the circuit when 
placed on a 7" x 14" panel. The vari- 
ous parts in the isometric are lettered 
to correspond with those on the wiring 



diagram and the wires are numbered in 
agreement with the numbering of the 
wires in Fig. 5. This enables the reader 
to follow across from wiring diagram to 
the isometric assembly. 



=TEN IN ONE!=! 

Ten issues of Radio Age, up to and 
including the April, 1923, number, 
have been bound in heavy cloth. 
One of these fine volumes will be 
sent postpaid to any address with 
one year's subscription to Radio 
Age for the special price of $3.50. 
The book has many hook-ups 
and articles you may have missed. 
Send money order or check to 

RADIO AGE, INC., 

500 N. Dearborn St., Chicago, 111. 

"Let our Hook-ups Be Your Guide" 



A MARVEL OF 
EFFICIENCY and 
SELECTIVITY 




TUNING 
UNIT 



FOR ANY CIRCUIT 



This new method of parallel motion, 
coupling the flat magnetic fields pro- 
duced by these coils, gives a much 
more efficient and smooth variation of 
mutual inductance than is possible 
with the old-fashioned variometer and 
variocoupler. 

Try this in your favorite circuit and 
hear stations you never heard before. 

At your dealers dj*C Af| 
or POSTPAID, «j)O.UU 




PFANSTIEHL SILENCER 




A Wave Trap using inductance of the spider web 
type, woven with great care and developed to 
high degree of selectivity. 

Ask your dealer 

K5- $8.00 



Other Pfanstiehl Pure 
Inductances 







List 


Wave 




Turns Price 


Length 


P-201 


25 


$ .55 


100-340 


P-202 


35 


.59 


125-470 


P-203 


50 


.65 


170-650 


P-204 


75 


.74 


220-960 


P-205 


100 


.90 


300-1300 


P-206._ 


150 


1.10 


470-1980 




Ultra Audion 
Reinartz 




$0.95 


Pfanstiehl 




1.75 



(The Pfanstiehl Inductance is a highly 
effective coil f>r the Reinartz circuit.) 

Above items at all good dealers or 
sent postpaid. 

Pfanstiehl 

Radio Service Co. 



HIGHLAND PARK, ILL. 

CHICAGO OFFICE, 33 SOUTH CLINTON STREET 



40 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 




The technical department sends out many replies lo questions in each day's mail. In order to assure prompt service to our subscribers the direct reply melhodhereafler 
must be restricted to those fans who are on our subscription list. Fans who are not subscribers may obtain this service by enclosing 50 cents with their question and the reply 
will be mailed at once, accompanied by circuit diagram where illustration is needed. All inquiries should be accompanied by self-addressed and stamped emelope. 



G. S. B., Kenosha, Wis. 

Question: After reading your article 
in the January issue, I proceeded to build 
an Eliminator as from your description. 
I built this especially to be able to elim- 
inate Zion, 111., Station WCBD. Inas- 
much as they are only about six miles 
from us we like to get them out in some 
manner. I used a 23 plate condenser and 
constructed -the windings as you specified. 
The coil I have fitted over and around the 
condenser. I used it tonight on a try 
out as WCBD was shooting with full 
power. The Eliminator stopped them 
dead, not a squawk from the station. 
I find however, that I can't tune any 
near stations by a rather wide margin. 
The Eliminator was hooked between 
the ground and antenna as illustrated in 
figure 9. When I tune out WJAZ, I 
am unable to tune in KYW. Why? 

Answer: First of all I am of the opin- 
ion that you are not quite familiar with 
the action of the filter, judging by your 
description. The tuning of the filter 
requires patience, and perseverance to 
obtain the best results. Have you tried 
any of the other permutations possible 
with the filter to find out about the 
action with different connection? Also 
would advise that you place a 25 turn 
honeycomb coil in the antenna lead, 
which assists the filter in its purpose by 



3" TUBS 



raising the fundamental wave of the 
antenna slightly. 



E. S. F., Chicago, 111. 

Question: As a subscriber to RADIO 
AGE I ask you to kindly print a circuit 
showing two stages of radio frequency 
amplification to the standard Armstrong 
Regenerative circuit. The circuit may 
use either tuned or untuned radio fre- 
quency transformers. 

Answer: Figure 1 shows the diagram 
you desire. 



Westinghouse Aeriola Sr., two stage 
autio frequency amplifier? 

Answer: The amplifier as described 
may be used as a third stage with a 
tremendous increase in volume by con- 
necting the output of the amplifier of the 
set you are now using to the input of the 
Push-Pull amplifier as described in the 
January issue. The loud speaker should 
be connected to the output of the Push- 
Pull amplifier. 



C. T., Chicago, III. 

Question: As a subscriber to your 
magazine would like it very much if you 
would send me diagrams and information 
on a five tube outfit 2 RF and 2 AF 
amplification using a loose coupler. I 
have a standard loose coupler and 43 
plate condenser. 

Answer: A diagram of the type you 
mention was printed in the November 
1923 issue of RADIO AGE on page 18. 
The diagram calls for the type of ap- 
paratus you mention. 




J. M. P., Dayton, O. 

Question: Will you kindly advise me 
if your Push-Pull amplifier as outlined on 
Page 15 of the January RADIO AGE can 
be added to my receiver which is of the 



1-3*1£6- 



R. E. M., Stratton, Nebr. 

Question: I recently constructed a set 
using the Rosenbloom circuit which you 
published in the January issue of RADIO 
AGE. Your diagram calls for a .0005 MF 
condenser between the antennae and 
variometer. I tried connecting it up, 
but it made a buzzing similar to that 
caused by a loose connection. Can you 
explain this? By leaving out the con- 
denser I was able to pick up Los Angeles 
and San Francisco on the West Coast, 
and WJAZ, WOC, WOS, WHB, KFKA 
and WLAG with ease. I used fifty feet of 
ordinary insulated low tension wire 
strung around the garage for an antenna. 
Is this a good performance with a single 
tube? If you can suggest a reason for the 
performance of the condenser will be 
very much obliged. 

Answer: The action you speak of is 
(Continued on page 42.) 



I — : I If— [ I — — | — 



./ i t\. 



&ROUND 




/&-3o f 



67- 90 V 



Fig. I 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



41 



Avoid "QRM" 

(Continued from page 21.) 

only half (or even less than half) of the 
tuning coil in the set, and doing your 
tuning with a variable condenser as I 
have just described. 

Next let us take up type No. 11, the 
plain or non-regenerative audion detector 
used with a single tuned aerial circuit. 
There are not many of these in use, so 
far as I know, but they tune best when 
a series condenser in the aerial is used as I 
have explained for the simple crystal set. 
Crystal Receivers 

If your single tuned crystal set has the 
good features described above and still 
is not sharply enough tuned, you must go 
higher up the list. The easiest thing to 
do is to convert it into a type No. 10 
set, which is the double-tuned crystal 
receiver. The most important thing 
you have to do for this conversation is to 
wind a coil of about forty turns of, say, 
No. 24 double cotton covered wire on a 
tube 3 1-2 or 4 inches in diameter and 
connect it in series with a variable con- 
denser between your aerial and ground, 
which are to be disconnected from your 
single-tuned set. You then connect 
the aerial and ground binding posts on 
the set together by a wire if there is a 
variable condenser in the set. If there 
is none in the receiver, you connect one 
between these same binding posts. Then 
you put the new coil in line with and 
fairly close to the coil in the receiver and 
go ahead. 

To adjust a double-tuned outfit of the 
kind that this now is, you must have both 
of the variable condensers at the right 
setting at the same time. Of course this 
correct scale, reading is different for 
every wave frequency, so the double- 
tuning feature gives a sort of combina- 



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consisting of the following: 

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1 Tube socket, 1 base board. 

1 Micadon grid condenser and leak. 

1 6-ohm rheostat, 7 binding posts. 

4 ft. hookup wire, 3 ft. insulating tubing. 

1 Inductance coil — ■ready wound. 

1 — .001 fixed condenser 

1 Pair head phones. 

1 Dry cell vacuum tube. 

1 *'A" battery and 1 B battery. 

100 ft. aerial wire — 25 ft. ground wire. 

2 Aerial insulator, ground clamp and nstruction 
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At last you have under one cover 
a Complete Radio Handbook 

JUST OUT 
514 PAGES 

Compiled by 

HARRY F. DART, 
B.S.E.E. 

Formerly with the 
Western Electric 
Co., and ' S. 
Army Instructor 
of Radio. Tech- 
nically edited by 
F. H. Doane. 




tion lock effect that is harder to adjust 
but more selective than the single tuned 
circuit. You will find that the farther 
the two coils are apart, within reason, 
the better the selectiveness. Of course 
the crystal and telephone side-circuit 
should be connected across one half or 
less of the coil in the original set, as ex- 
plained with regard to the No. 12 type 
of receiver. 

A type of No. 11 single tuned audion 
set may be converted into a No. 9 double- 
tuned set in this same way, and will be 
much more nearly free from interference. 

The next most selective set, as we go 
up the list, is type No. 8. This is the 
multiple-stage radio- frequency-amplifier 
outfit that uses fixed or untuned radio 
frequency transformers. Many of the 
popular "reflex" sets are made up in this 
way. Nearly all of them include a 
stabilizer or variable resistance for ad- 
justing regeneration, but many are not 
sharply tuned in spite of that. It would 
take a long time to diagnose and explain 

the faults in design, in construction and 20,000 SOLD 

in operation that are common in these ^j more need yQU turn frQm book ^ 
outfits; consequently the most helpful J>| book, hoping to find what you want, 
thing I can do is to suggest that if you K ig aU h in crammed full 

have a set of this type you can probably of iWe radio detaU> Written 

improve its selectiveness by making up •„ ^ j b engineers for lay- 

and adding to it a separate antenna- m ni „ , A. Z ■ ±11 

. . & .^ , T , , ., , men. Clears up the mysteries, tells you 

tuning circuit such as I have described , . . . , . , , . 

f ,, b . , . rr^u-j ^^ what you want to know. A complete m- 

tor the crystal set. It this does not stop . . ,, • .. , . , 

. . t , , .„ ... H dex puts everything within your reach 

your interference troubles you will either ■ % \ 

i . ., t 1 • , ina few seconds, 

have to improve the general design of 

vnnr set or pl«p crpf annfhpr that is Vipffpr IT EXPLAINS: Electrical terms and 

your Set Or else get anotner tnat IS Detter circuits, antennas, batteries, genera- 

or higher up the list. tors and motors, electron (vacuum) 

We now come to type No. 7, which is 2£ e \„X y ££££$ ^mpSfcauS! 

the popular single-circuit regenerator. broadcast and commercial transmit- 

A lare-e nronortion of interference en- ter ? an , d receiver ?> super-regeneration, 

n large piupuruuii oi^ liiLenereiice en codes, license rules. Many other fea- 

countered by radio listeners may be tures. 

attributed to the inefficiency of receiving Under one cover. Yes, it is all in 

sets of this design. one volume of 514 pages of clear type 

with hundreds of diagrams and illustra- 

Recognizfrlg Voices tions. Takes the place of eleven or more 

Recently, a new announcer handled specialized texts, each costing from two 

his first program through WEAF. On to ten times the dollar you pay for this 

returning home he asked his mother single book. Belongs in every radio- 

whether she had heard the program equipped home, on every amateur's table, 

during the afternoon. "Yes" she re- send $1 to-day and get this si4-page l.C.S. 

sponded, but made no Comment. A Radio Handbook — the biggest value in radio 

little surprised he asked how she had to ' da y- Money back if not satisfied. 

liked the announcing. Again a mono- r tear out here , 

syllabic answer. Finally he learned to ) international correspondence schools | 

his astonishment that his mother had I Box 8781 ' Scranton ' Penna - I 

. 1 1 • ■ r 11 I I enclose One Dollar. Please send me — nost- I 

not recognized his VOlCe SO Carefully I paid— the 514-paee I. C. S. Radio Handbook. 1 

had he applied the art of correct tone I u *» J un ^ erst00d tllat lt , I am n °' entirely | 

. ... . . .1 satisfied I may return this book within five i 

and enunciation tor the microphone in I days and you will refund my money. 

acquiring a "radio" voice. 

On the aother hand, not many days I Name 

previous, another new announcer had I 

been heard for the first time through j Address ' 

WEAF for a few brief special announce- 

ments. Later in the evening, a friend 

who had not seen or heard of the an- If your newsdealer has sold out 

nouncer for more than three years tele- his supply of Radio Age you are 

phoned a message of congratulation, likely to miss just the hook-up that 

He had not questioned for a moment but y OU have been looking for. To 

that the announcing voice was that of avoid any such chance fil , out the 

his friend so perfect and convincing was Qn , n thJs isgue am , gend |n 

its reproduction. . * 
1 subscription. Then you will be safe. 

And don't forget that with each 

subscription at the special price of 

$2.50 a year. We send you free the 

popular Reinartz Radio booklet 

FREE. Address Radio Age, 500 N. 

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$ 



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eceiving 
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have a record of 3,500 miles reception 



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5133 Woodworth St. Pittsburgh, Pa. 



42 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



Troubleshooter 

(Continued from page 40.) 
no doubt caused by some queer freak in 
your wiring and arrangement of parts to 
supply the necessary capacity. It might 
be that your condenser was shorted, 
causing the buzz you speak of, and when 
you omitted it from the circuit the 
remaining wires and apparatus connected 
to the set furnished enough capacity to 
offset its removal from the circuit. The 
list you enclosed is a good list consider- 
ing the antenna you mention. 



Figure 2. 



N. D. S., Mendon, Mich. 

Question: Can you offer any sugges- 
tions how I can remedy my set Reinartz 
of its habit of fading away and then 
coming back strong as ever again, and 
sometimes even stronger. I use two 
stages of audio frequency. I have a 
reflex transformer. Would like to know 
if I can add one stage of radio to the 
present set and use that transformer. 
Will you send me a hookup using a 
coupled circuit tuner with a variometer 
and a condenser. I want one that will 
tune easy. 

Answer: Fading, I am sorry to say, 
is a phenomenon that we mere human 
beings cannot control, and about which 
we know very little. If you keep your 
batteries up to the mark, see to it that no 
loose connections exist etc., it is about 
all you can do. The transformer you 
mention will not efficiently function in 
the circuit. A circuit of the type you 
desire was printed in the October issue of 
RADIO AGE on page 5. The diagram 
showing two stages of amplification was 
printed in the December issue. 



G. R. S., Clinton, la. 

Question: I have completed the 4 tube 
neutrodyne, on which I can get stations 
but not loud. I can put the antenna on 
the detector and get most of the stations 
just as loud as without the RF. All my 
batteries are OK, and I am using good 
parts. I find that I have to force the 
radio frequency tubes considerably to 
get results. Would appreciate your 
giving me some general hints on the 
adjustment of the set. 

Answer: Would suggest that your 




%-3o 



limitations are caused by insufficient 
capacities in the neutrodons to balance 
the valves properly. A piece of copper 
about 1 1-2 inch square for each plate of 
the condenser as illustrated on the en- 
closed sketch should help. Adjust the 
neutrodons with the condenser settings at 
about 55. When adjusting the neutro- 
dons, it is a good plan to pick out a good 
loud signal, or you may not find the 
proper place to balance the set. 



S. E. M., Washington, D. C. 

Question: I am a subscriber to your 
wonderful magazine, which I think is a 
great help to all radio fans, and noticing 
that you offer assistance, desire a hookup 
of a single tube set in which I can use 
the following list of apparatus: 1 23 
plate condenser, 1 variometer, 1 vario- 
coupler, WD 11 tube and accessories. 

Answer: A circuit adaptable to your 
apparatus appeared in the July, 1923, 
issue of RADIO AGEon page 19. The set 
is a regenerative one, and we have seen 
it giving very good results. 



H. G. G., Long Beach, Cal. 

Question: Will you kindly publish 
the best known hook-up for the 3 coil 
Honeycomb set using Duo-lateral wound 




coils for waves from 200 to 500 meters. 
Object sought — to cut out local broad- 
casts and bring in long distance. Desire 
to use 300 tube on detector if OK, and 
would appreciate a list of parts. Your 
RADIO AGE is a loud speaker, and 1 
wish you great success. 

Answer: I am printing in Figure 2 
the proper connections for the parts you 
mention. If you are having trouble in 
cutting out local stations why not build 
one of the rejectors or eliminators as de- 
scribed in the January issue of RADIO 
AGE? Thank you very much for your 
comment on RADIO AGE. We hope 
you will find it more interesting and in- 
structive in the future. 



C. F. G., Jr., St. Louis, Mo. 

Question: I have been trying the 
Kopprasch circuit for some time which 
was described in April, 1923, issue but I 
don't get the proper results. I saw in 
your answer to D. P. of Racine, Wis., 
in the November, 1923, issue several 
suggestions as to the improvement of 
reception with this circuit, but after 
carrying them out find my results little 
changed. I am afraid that I don't quite 
understand the connections of the vario- 
meters. That is I don't quite get what 



COIL 



Wro/t mtcvz 

DlR£Cr/OM OF CV/AIOlMrS 



BPLflTF 



MOUNTING OF VARIOMETERS AND TUBE 

TObSID -f 
VARIOMETER^ VARIOMETER. _l~"^ 

TO~7iPC 



WfrHO 




Figure 3. 



<§> * 



seize? 



PARAUSi. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



Complete Corrected List of U. S. and Canadian 

Broadcasting Stations 



43 



Complete Each Issue 

THE list of broadcasting stations on these pages is brought up to date each month by 
additions of new stations and deletion of those which have suspended operation. The list 
is the product of a vast volume of correspondence and its completeness is due in large 
measure to the assistance of our special news service in Washington, D. C. Suggestions, correc- 
tions and additional data will be welcomed from readers and broadcasters. 



KDKA Westinghouse Eleotrto & Mfg. Co... 

KDPM Westinghouse Eleotrto & Mfg. Co... 

KDPT Southern Electrical Co 

KDYL Telegram Publishing C#. 

KDYM Savoy Theatre... 



Ware 

length 

..East Pittsburgh 326 

...Cleveland. Ohio 270 

..San Diego, Calif. 244 



-Salt Lake City, Utah 360 

San Diego. Calif. 2S2 

KOYQ Oregon Institute 9! Technology _ Portland. Oreg. 360 

KDYW Smith Hughes & Ce. ...Phoenix. Ariz. 360 

KDYX Star Bulletin _ Honolulu. Hawaii 360 

KDZB Frank E. Siefert Bakersfleld, Calif. 240 

KDZE The Rhodes Co. __ Seattle. Wash ' 



KDZF Automobile Club «f Southern California Los Angeles, Calif. 

KDZI Electric Supply Co...._ _ Wenatchee, Wash. 

KDZQ Nichols Academy of Dancing _ - - Denver, Colo. 

KOZR Bellingham Publishing Co. _ Bellingham. Wash. 

KFAD McArthur Bros. Mercantile Co Phoenix, Ariz. 

KFAE State Collge of Washington Pullman, Wash. 

Western Radie Corp. - .....Denver, Colo. 

University of Coloradt. _ ; Boulder, Colo. 



KFAF 
KFAJ 
KFAN The Electric Shop.. 



455 
278 
360 
360 
261 
360 
330 
360 
360 



..Moscow, Idaho 360 

KFAR Studio Lighting Service Co. (O. K. Olsen)..- _ Hollywood, Calif. 280 

KFAU Independent School District of Boiso City, Boise High School, Boise, Idaho 270 

KFAV Abbot Kinney C»..._ — Venice, Calif. 224 

KFAW The Radio Den (W. B. Ashford) Santa Ana, Calif. 

KFAY W. J. Virgin _ 

KFBB F. A. Buttrey & C». 
KFBC W. K. AzbllL. 



280 

..Medford, Oreg 283 

Havre. Mont. 360 

..San Diego, Calif. 278 



KFBE Reuben H. Horn _ _ San Luis Obispo, Calif. 360 

KFBG First Presbyterian Church „ Tacoma, Wash. 360 

KFBK Kimball-Upson Ce _ _ - Sacramento, Calif. 283 

KFBL Leese Bros _ _ _ Everett, Wash. 224 

KFBS Trinidad Gas & Electric Supply Co. and the Chronicle News 

Trinidad, Colo. 360 

KFBU The Cathedral (Bishop N. S. Thomas) _ _ ....Laramie, Wyo. 283 

KFCB Nielsen Radio Supply Co _ Phoenix. Ariz. 238 

KFCD Salem Electric Co. (F. S. Barton) Salem. Oreg. 360 

KFCF Frank A. Moore _ Walla Walla. Wash. 360 

KFCH Electric Service Station (Inc.) Billings, Mont. 360 



KFCK Colorado Springs Radio Co _ Colorado Springs, Colo. 



KFCM Richmond Radio Shop (Frank T. Doelng).. 

KFCP Ralph W. Flygare 

KFCV Fred Mahaffey, Jr. 

KFCY Western Union College 

KFCZ Omaha Central High SchooL. 

KFDA Adler-s Music Store 

KFDD St. Michaels Cathedral... 



..Richmond. Calif. 



258 
360 



..Ogden. Utah 360 
..Houston, Tex. 360 



. — Tucson, Ariz. 

..Corvallis. Oreg. 



KFDH University of Arizona. 

KFDJ Oregon Agricultural College.. 

KFDL Knight-Campbell Music Co _ Denver, Colo. 

KFDO H. Everett Cutting _ _ - Bozeman, Mont. 

KFDR Bullock's Hardware & Sporting Goods (Robert G. Bullock). York, Nebr 

KFDU Nebraska Radio Electrio Co Lincoln, Nebr. 

KFDV Gilbrech & Stlnson Jayetteville, Ark. 

KFDX First Baptist Church. _ Shreveport, La. 

KFDY South Dakota State College of Agriculture and Mechanic Arts, 

Brookings, S. Dak. 



KFDZ Harry O. Iverson. 

KFEC Meier & Frank C». 

KFEJ Guy Greason 

KFEL Winner Radio Corp. 



..LeMars, Iowa 252 

Omaha, Nebr. 258 

.....Baker, Oreg. 360 

..Boise, Idaho 252 
360 
360 
360 
248 
360 
240 
360 
360 

360 



...Minneapolis. Minn. 23 1 



..Portland, Oreg. 
..Tacoma, Wash. 

Denver, Colo. 

..Oak, Nebr. 



360 
360 
360 
360 



KFEQ J. L. Scroggln ........ 

KFER Auto Electric Service Co. _ _ .Fort Dodge, Iowa 231 

KFEV Radio Electrio Shop _ _ _ _ -_ Douglas, Wyo. 263 

KFEX Augsburg Seminary _ _ _ Minneapolis, Minn. 261 

KFEY Bunker Hill & Sullivan Mining & Concentrating Co Kellogg. Idaho 360 

KFEZ American Society of Mechanical Engineers (F. H. Schubert,) 

St. Louis. Mo. 360 

KFFB Jenkins Furniture C». _ _ _ Boise. Idaho 240 

KFFE Eastern Oregon Radie Ce _ _ Pendleton, Oreg. 360 

KFFO Dr. E. H. Smith. Hlllsboro, Oreg. 229 

KFFQ Markshefrel Motor Ce. _ Colorado Springs, Colo. 360 

KFFR Nevada State Journal (Jim Kirk) - _ _ _.. Sparks, Nev. 226 

KFFV Graceland College _ Lamoni, Iowa 360 

KFFX McGraw Co. Omaha, Nebr. 278 

KFFY Pincus & Murphy...- _. 

KFFZ Al. G. Barnes Amusement Co... 

KFGC Louisiana State University _ _ Baton Rouge, La, 

KFGD Chickasha Radio & Electric Co _ _ Chickaaha, Okla. 

KFGH Leland Stanford University _ _ Stanford University, Calif. 360 

KFGJ Missouri National Guard, 138th Infantry _ St. Louis. Mo. 266 

KFGL Arlington Garage _ _ Arlington. Oreg. 234 

KFGQ. Crary Hardware C» - _ Boone, Iowa 226 

KFGV Heldbreder Radie Supply Co. .Utica. Nebr. 224 



..Alexandria, La. 275 
..Dallas, Tex. (portable) 226 



254 
248 



KFGX First Presbyterian Church _ _ _ Orange. Tex. 

KFGZ Emmanuel Missionary College _ .Berrien Springs. Mich. 

KFHA Western State College of Colorado _ Gunnison, Colo. 

KFHB Rtalto Theater (P. L. Beardwell) Hood River, Oreg. 

KFHD Utz Electric Shop Ce. St. Joseph, Mo. 

KFHF Central Christian Church _ _ Shreveport, La. 



KFHH Ambrose A. McCue. 

KFHJ 

KFHR 



..Neah Bay, Wash. 



250 
268 
252 
280 
226 
266 
283 
360 
270 



Fallon & Co Santa Barbara, Calif. 

Star Electric & Radie Co _ _ Seattle. Wash. 

KFHS Clifford J. Dow _ _ Llhue. Hawaii 275 

KFHX Robert W. Nelson _ —Hutchinson. Kans. 229 

KFI Earle C. Anthony (Inc.) _ Xos Angeles, Calif. 469 

KFIB Franklin W. Jenkins. _ ,. -.St. Louis. Mo. 244 

KFID Ross Arbuckle's Garage Ma. Kans. 246 

KFIF Benson Polytechnic Institute _ _ Portland, Oreg. 360 

KFIK Gladbrook Electrical Co Gladbrook. Iowa 234 

KFIL Wlndisch Electric Farm Equipment Co _ Louishurg, Kans. 234 

KFIO North Central High School -...Spokane, Wash. 252 

KFIQ Yakima Valley Radio Broadcasting Association Yakima, Wash. 224 

KFIU Alaska Electrio Light & Power Co Juneau, Alaska 226 

KFIV V. H. Broyles _ Pittsburg. Kans. 240 

KFIX Reorganized Church ef Jesus Christ of Latter Day Saints 

Independence. Mo. 240 

*PIY Brott I/aboraterlen _ Seattle. Wash. 236 

KFIZ Daily Commonwealth and Oscar A. Huelsman... .Font? du Lac, Wis. 278 

KFJB Marshall Electrical Co Marshalltown, Iowa 248 

KFJC Seattle Post Intelligencer Seattle. Wash. 233 

KFJD Weld County Printing & Publishing Co Greeley. Colo. 



KFJF National Radio Manufacturing Co _ Oklahoma Cltv, Okla. 

KFJI Liberty Theatre (E. E. Marsh) —.Astoria. Oreg. 



KFJK Delano Radio and Electrio Co— 



238 
252 
252 



KFJL Hardsacg Manufacturing Co. 

KFJM University of North Dakota 

KFJR Ashley C. Dixon & Son 

KFJV Thomas H. Warren 

KFJW Le Grand Radio Co.. 



KFJX Iowa State Teachers' College.. 



Ottumwa, Iowa 242 

Grand Forks, N. Dak. 229 

-Stevensville, Mont, (near) 258 

Dexter, Iowa 224 

_ _ Towanda, Kana. 226 

..Cedar Falls, Iowa 229 



KFJY Tunwall Radio Co _ Fort Dodge, Iowa 248 

KFJZ Texas National Guard, One hundred and twelfth Cavalry Fort Worth. Tex. 254 

KFKA Colorado State Teachers College _ _ -...Greeley,- Colo. 248 

KFKB Brinkley-Jones Hospital Association. _ — Milford. Kans. 288 

KFKH Denver Park & Amusement Co _ _ .Lakeside, Colo. 228 

KFK9 Conway Radio Laboratories (Ben H. Woodruff).— Conway, Ark. 224 

KFKV F. F. Gray _ _ Butte. Mont. 283 

KFKX Westinghouse Electric & Manufacturing Co Hastings, Nebr. 288 

KFKZ Nassour Bros. Radio Co _ - Colorado Springs, Colo. 234 

KFLA Abner R. Willson _ Butte, Mont 28S 

KFLB Signal Electrio Manufacturing Co Menominee, Mich. 248 

KFLD Paul E. Greenlaw _ — Jfranklinton. La. 234 

KFLE National Educational Service Denver, Colo. 268 

KFLH Erlckson Radio Co Salt Lake City, Utah 261 

KFLP Everette M. Foster Cedar Rapids, Iowa 240 

KFLQ Bizzell Radio Shop Little Rock, Ark. 261 

KFLR University of New Mexico Albuquerque, N. Mex. 254 

KFLU Rio Grande Radio Supply House _ San Benito. Texas 236 

KFLV Rev. A. T. Frykman _ Rockford. 111. 229 

KFLW Missoula Electric Supply Co - Missoula. Mont. 234 

KFLX George Roy Cloiuh _....._ Galveston, Tex. 240 

KFLY Fargo Radio Supply ....Co Fargo, N. Dak. 231 

KFLZ Atlantic Automobile Co _ _ _ Atlantic, la. 273 

KFMQ University of Arkansas - :...._ Favetteville, Ark. 263 

KFMR Morningside College _ _ Sioux City. Iowa 261 

KFMS Fi-i.-in.iith Dept. Stoia...._ _ Duluth. Minn. 275 

ICFMT Dr. George W. Young _ Minneapolis, Minn. 231 

KFMU Sn-vens Bros _ _ San Marcos. Texas 240 

KFMW M. G. Sateren Ilnushton. Mich. 266 

KFIWX Carleton College _ Northfield, Minn. 283 

KFMY Boy Scouts of America _ Long Beach, Calif. 229 

KFMZ Roswell Broadcasting Club Roswell, N. M. 250 

Tacoma Daily Ledger - Tacoma. Wash. 



KGB 

KGG 

KGN 

KGO 

KGU 

KGW 

KGY 

KHJ 

KHQ 

KJQ 

KJR 

KIS 

KLS 

KLX 



Hallock & Watson Radio Service.. 
Northwestern Radio Mfg. Co. 



252 
.Portland. Oreg. S60 
..Portland. Oreg. 380 



General Electric Co Oakland. Calif. 312 

Marion A. Mulrony Honolulu, Hawaii, Walkikl Beach. 360 

Portland Morning Oregonlan..- „ Portland, Oreg. 492 

St. Martins College (Rev. Sebastian Ruth), Lacy Wash. 258 



Times-Mirror Co _ 

Louis Wasmer,. 
C. O. Gould... 



. Xos Angeles. Calif. 395 

360 



..Seattle. Wash. 
..Stockton, Calif. 360 
..8eattle. Wash. 270 



Northwest Radio Service Co. _. 

Bible Institute of Los Angeles _ Xos Angeles, Calif. 360 

Warner Brothers Radio Supplies Co Oakland. Calif. 360 

Tribune Publishing Co _.. . . ..Oakland, Calif. 509 

KLZ Reynolds Radio Co Denver, Colo. 509 

KM J San Joaquin Light & Power Corp Fresno, Calif. 273 

KMO Love Electrio Co .Tacoma, Wash. 369 

KNT Grays Harbor Radio Co. (Walter Hemrlch).— _ Aberdeen, Wash. 26S 

KNV Radio Supply Co Los Angeles. Calif. 258 

KNX Electric Lighting Supply Co _ Los Angeles, Calif. 368 

KOB New Mexico College of Agriculture & Mechanic Arts 

State College. N. Mex. 369 

Detroit Police Department _ Detroit, Mich. 236 

Hale Bro3 _ _ San Francisco. Calif. 423 

Apple City Radio Club _ Hood River, Oreg. 360 

Doubleday-Hiil Electric Co .'. Pittsburgh, Pa 



KOP 
KPO 
KQP 
KQV 
KQW 
KRE V C Battery & Electric Co. 



360 
Charles D. Hen-old.. _ _ _ San Jose, Calif. 360 



KRE V C Battery & Electric Co _ Berkeley, Calif. 278 

KSD Post Dispatch (Pulitzer Pub. Co.) St. Louis. Mo. 548 

KSS Prest & Dean Radio Co. and Radio Roaearch Society of Long Beach, 

Calif. _ Xong Beach. Calif. 360 

KTW First Presbyterian Church _ _ _ Seattle, Wash. 880 

KUO Examiner Printing Co San Francisco, Calif. 360 

KUS City Dye Works & Laundry Co Xos Angeles. Calif. 360 

KUY Coast Radio Co. JE1 Monte, Calif. 258 

KWG Portable Wireless Telephone Co __ Stockton. Calif. 360 

KWH Los Angeles Examiner. - _ Xos Angeles, Calif. 360 

KXD Modesto Herald Publishing Co.- Modesto, Calif. 252 

KYQ Electric Shop Honolulu. Hawaii 369 

KYW Westinghouse Electric & Mfg. Co _ Chicago, 111. 638 

KZM Preston D. Allen __ _ Oakland, Calif. 360 

KZN The Beseret News _ Salt Lake City. Utah 860 

KZV Wenatchee Battery & Motor Co _.._ Wenatchee. Wash. 360 



WAAB Valdemar Jensen.. 

WAAC Tulane University 

WAAD Ohio Mechanics Institute 

WAAF Chicago Daily Drovers Journal.... 

WAAK Gimbel Brothers 

WAAM I. R. Nelson Co 

WAAN University of Missouri.. 



..New Orleans, La. 268 

..New Orleans, La. 368 

—Cincinnati, Ohio 360 

..Chicago, 111. 288 



-Milwaukee, Wis. 280 

Newark, N. J. 263 

234 
380 
360 
268 



-Bristow. Okla. 233 



— _ _ Columbia, Mo. 

WAAW Omaha G'aln Exchange. _ _ Omaha, Nebr. 

V/AAZ Holllster-Mlller Motor Co. _ Emporia, Kans. 

WARA Lake Forest College _ Lake Forest, 111. 

WABB Dr. John B. Lawrence _ __ Harrisburg. Pa. 268 

WABC Fulwider-nrimes Battery Co.— _ Anderson. Ind. 220 

WABD Parker High School Dayton, Ohio 283 

WABE Young Men's Christian Association. .Washington, D. C. 283 

WABG Arnold Edwards Piano Co _ Jacksonville, Fla. 248 

WABH Lake Shore Tire Co _ Sandusky, Ohio 240 

WABI Bangor Railway & Electrio Co Bangor, Mc. 240 

WABJ The Radio Laboratories South Bend, Ind. 240 

WABK First Baptist Church Worcester, Mass. 252 

WABL Connecticut Agricultural College ...Storrs, Conn. 283 

WABM F. E. Doherty Automotive and Radio Equipment Co Saginaw, Mich. 254 

WABN Waldo C; Grover. _ La Crosse, Wis. 244 

WABO Lake Avenuei Baptist Church _ Rochester. N. Y. 252 

WABP Robert F. Wei nig _ _ .Dover. Ohio 266 

WABQ Ifavcrfnrd College Radio Club Haverford, Pa. 261 

WABR Scott High School. N. W. B. Foley Toledo, Ohio 270 

WARS Essex Manufacturing Co Newark, N. J. 244 

WABT Holiday-Mall, Radio Engineers Washington, Pa. 252 

WABU Victor Talking Machine Co _ Camden, N. J. 226 

WABV John H. DeWitt, ,Tr .Nashville, Tenn. 263 

WABW College o£ Wooster. _ _ Wooster, Ohio .234 

WABX Henry B. Joy _ Mt. Clmens. Mioh. 270 

WABY John Magaldl, .Tr - .Philadelphia, Pa. 242 

WABZ Coliseum Place Baptist Church —New Orleans, La. 263 



44 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



Troubleshooter 

(Continued from page 42.) 
you mean by series and parallel connec- 
tions. How can I determine the proper 
way to wind the antenna coil. I am en- 
closing some sketches which I trust will 
help clear my trouble. My variometers 
seem to be wound from right to left while 
the antennal coil is wound from left to 
right. I feel sure that my trouble lies 
in the connecting of the variometers in 
series and parallel. Can you help me? 
Answer: I am printing in Figure 3 
some suggestions for wiring up the vario- 
meters of the Kopprasch circuit, and feel 
sure that it will clear up the difficulty 
without trouble. If you have the an- 
tenna coil wound in the opposite direc- 
tion to the STATOR coils of the vario- 
meter you should not have any trouble 
providing that you have the connections 
of the rest of the set correctly made. 



As long as you do not manufacture the 
set on a large scale, no one will interfere 
with your selling sets to friends. Sepa- 
rate batteries must be used on the ampli- 
fier and oscillator circuits. 



H. R. H., Jamestown, N. Y. 

Question: I am building the eight 
tube super described in your November 
issue, and am thinking of using the resis- 
tance coupled amplifiers instead of the 
Audio Transformer coupled type of am- 
plification. I would like to get a diagram 
of the super with the following diagram 
added to it instead of the one stage of 
audio frequency as shown. Would like 
to know that method is used in tuning 
an inside loop circuit. Is there any law 
against my selling this set to a friend? 
Can I use U V 200 tubes for oscillator 
and detectors in this circuit? Is it possi- 
ble to take taps off the B battery used in 
the amplifier c rcuits for the oscillator 
circuit? 

Answer: You can use the resistance 
coupled amplifier you submitted a circuit 
of by merely connecting the input of the 
resistance coupled amplifier to the out- 
put of the second detector at the points 
indicated for the primary of the audio 
transformer. The same batteries as 
are used on the radio amplifier and second 
detector may be used on this amplifier. 
When a loop is used with the circuit you 
mention the connections are made accord- 
ing to the diagram shown in Figure 5. 



Antenna Analogy 

(Continued from page 10.) 
between the two parts. Every aerial 
contains a certain amount of inductance 
and capacity and the primary coil of the 
set which is in circuit with it furnishes a 
large amount of inductance. The capac- 
ity offered by the aerial is due to the fact 
that the ground acts as one conductor 
and the aerial as the other. The higher it 
is placed, the less the capacity and the 
greater the length of the vertical part, 
which will intercept more lines than if it 
were short. If the aerial has too much 
capacity, it may be compensated for, by 
including a variable condenser in its cir- 
cuit. This will also aid in tuning the set. 

As an illustration of just why capacity 
is necessary in the aerial Figure 8 is sub- 
mitted. This consists of two closed water 
tanks connected by a pipe and partly 
filled with water. A plunger which fits 
tightly in the pipe is arranged so that it 
can be moved back and forth from the 
outside. If the tanks are small, the 
plunger cannot move very far in either 
direction, due to the small capacity of 
the tanks, but if their size is increased, it 
will be possible to get a greater move- 
ment of the plunger. Letting the two 
tanks represent the aerial and ground 
and the plunger represent the current 
produced in the aerial and the lines of 
force, the power which moves the plunger, 
one can readily see how too small a ca- 
pacity would prevent a free movement of 
current of low frequency and why very 
little capacity would be necessary for 
high frequencies of short duration. 

From the description given here one 
always remembering that however it may 
be constructed to meet his particular 
needs, the ohmic resistance should be as 
low as possible, which means that the 
cross section of both the aerial and the 
ground wire should be as large as possible. 



Contact Across Pacific 

Tacoma, Wash. — An unknown Ameri- 
can radio operator situated in Tokio, 
Japan, recently sent a radio message to 
his mother at Cambridge, 111., through 
the amateur radio station, 7HG, in this 
city, operated by Charles York, marking 
the first two-way short wave communi- 
cation across the Pacific ocean. With 
only a fleeting contact, barely allowing 
time for the message to come through, 
York had considerable difficulty in 
distinguishing the foreign operator's 
call, JUPU. 

While the signals of amateur trans- 
mitters in the United States have been 
reported by ship operators in remote 
sections of the Pacific, and as distant 
as the island of Ceylon in the Indian 
ocean, this incident is the first in which 
an amateur has worked both directions 
across the 4,760 mile stretch of ocean. 
The message was delivered via the 
American Radio Relay League traffic 
system. 

The contact hardly had been made 
and the message copied when com- 
munication was interrupted by heavy 
interference. It was about 1:00 a. m. 
when York heard a station with pure 
CW calling on 200 meters and signing 
with the unfamiliar Japanese call. For 
a brief interval signals were good at 
both stations. 

The station operated by York is sit- 
uated on one of the highest hills in that 
country. He has done a great deal of 
long distance work, his best previous 
two-way record being to communicate 
with Canadian amateur station 1AC 
situated in Nova Scotia. He had also 
worked 6CEU in Hawaii and amateurs 
in every radio district in the United 
States with the exception of those in 
the second and fourth. 

His antenna is supported by a 65 foot 
pole at the free end and a 40 foot pole 
at the lead in end. It is a six-wire flat 
top 50 feet long with a counterpoise di- 
rectly underneath. The transmitter uses 
the Hartley circuit with two Telefunken 
D. R. P. tubes. 



IRON (ORE RADIO FRE.QU£NC\ 
rRAMSFORME&S 



6 7~OJ AOD/O 
TRANSFORMER 




BeurT&qy 9a- /zor 



ZOO - 4-00 OHM 
P07£N71OVIE7ER 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



45 



Complete Corrected List of U. S. and Canadian 

Broadcasting Stations 



WBAA Purdue University _ _ _ _ West Layayette, Ind. 360 

WBAD Sterling Electric Co _ Miniiuauoils, Minn. 360 

WbAH The .Dayton ue _ Minneapolis, Minn. 417 



WBAN Wireless Phone Corp ._ ._. _ 

WBAO James Millikln University _ _ 

WBAP Wortham-Carter Publishing Co. (bur Telegram).. 

WBAV Erner & Hopkins Co _ 

WBAW Marietta College.. _ 

WBAX John H. Stenger, Jr. _.. 

WBAY Western Electric Co.. 



..Paterson. N. J. 244 
..Decatur, 111. 360 



.-..Port Worth, Tex. 476 

Columbus, Ohio 390 

.Marietta, Ohio 246 

.... Wllkes-Barre, Pa. 360 

....New York, N. Y. 492 

.Newark. Ohio 240 

Pleading. Pa. 234 

WBBE Alfred R, Marty...- _ Syracuse, N. Y. 246 

WBBF Georgia School of Technology Atlanta, Ga. 270 

W3BG Irving Termiiva _ Mattapoisett, Mass. 240 

WBL T & H Badio Co _ Anthony, Kans. 261 

Pennsylvania State Police Butler. Pa. 286 

D. W. May, Ino Newark, N. J. 360 



WBBA Newark Radio Laboratories- 

WBBO Barbey Battery Service... 



WBR 
WBS 
WBT 
WBZ 



Southern Badio Corp _ Charlotte, N. C. 360 

Westinghouse Elec. & Mfg. Co Springfield, Mass. 337 

WCAD St Lawrence University Canton, N. Y. 280 

WCAE Kaufmann & Baer Co Pittsburgh, Pa. 462 

WCAG Clyde B. BandalL New Orleans. La. 268 

WCAH EntreHn Electrlo Co. Columbus. Ohio 286 



WCAJ Nebraska Wesleyan University... 

WCAK Alfred P. DanleL 

WCAL St. Olaf CoUege 

WCAM Villanova CoUege 



360 



..University Place, Nebr. 

Houston, Tex. 360 

-....Northfleld, Minn. 360 

Villanova, Pa. 360 

WCAO Sanders & Stayman Co Baltimore, Md. 360 

WPAP Chesapeake & Potomao Telephone Co Washington, D. C. 469 

WCAR Alamo Badio Electrlo Co _ _ San Antonio, Tex. 360 

WCAS William Hood Dunwoody Industrial Institute Minneapolis, Minn. 246 

WCAT South Dakota State School of Mines _ Bapid City, S. Dak. 240 

WCAU Durham & Co Philadelphia, Pa. 286 

WCAV J. C. Dice Electric Co _ Little Bock, Ark. 360 

WCAX University et Vermont _ Burlington. Vt. 360 

WCAY Kesselman O'DriscoU Co. _ — .Milwaukee. Wis. 261 

WCAZ Carthage CoUege Carthage. 111. 246 

WCBA Charles W. Heimbach. _. Allentown, Pa. 280 

WCBD Wilbur G. VoUva _ __ - Zlon, 111. 345 

WCK Stlx, Baer & Fuller Dry Goods Co _ St. Louis. Mo. 360 

WCM University of Texas Austin. Tex. 360 

WCX Detroit Free Press. „ Detroit, Mich. 517 

WDAE Tarapa Dally Times. Tampa, Fla. 360 

WDAF Kansas City Star .Kansas City, Mo. 411 

WDAG J. Laurance Martin. _ Amarillo, Tex. 263 

WDAH Trinity Methodist Church (South) El Paso, Tex. 268 

WDAK The Courant _ Hartford, Conn. 261 

WDAO Automotive Electrlo Co __ Dallas. Tex. 360 

WDAP Board of Trade Chicago. IU. 360 

WDAR Lit Brothers. _ Philadelphia. Pa. 395 

WDAS Samuel A. Walte Worcester. Mass. 360 

WDAU Slocum Kllburn. _ New Bedford. Mass. 360 

WDAX First National Bank (Appameose County Farm Bureau) 

Centerville, Iowa 360 

WDAY Badio Equipment Corp _ _ ......Fargo, N. Dak. 244 

WDBC Kirk, Johnson & Co. .Lancaster. Pa. 258 

WDZ James L. Bush Tuscola. 111.. Star Store Bldg. 278 

WEAA F. D. Fallain _ _ .Flint, Mich. 280 

WEAF American Telephone & Telegraph Co - New York, N. Y. 492 

WEAH Wichita Board of Trade __ Wichita, Kans. 244 

WEAI Cornell University _ _ _ Ithaca, N. Y. 286 

WEAJ University of South Dakota Vermilion, S. Dak. 283 

WEAM Borough of North Plainfleld (W. Gibson Buttfleld) 

— _ North Plainfleld, N. J. 252 

WEAN Shepard Co _ Providence. B. I. 273 

WEAO Ohio State University Columbus, Ohio 360 

WEAP Mobile Badio Co Mobile, Ala. 360 

WEAR Baltimore American & News Publishing Co Baltimore. Md. 360 

WEAS Hecht Co _.._ Washington, D. C. 360 

WEAU Davidson Bros. Co Sioux City. Iowa 360 

WEAY Iris Theatre (W1U Horowitz. Jr.) - Houston, Tex. 360 

WEB Benwood Co _ _ St. Louis. Mo. 360 

WEV Hurlburt- Still Electrical Co - Houston, Tex. 360 

WEW St. Louis University -St. Louis, Mo. 261 

WFAA Dallas News & Dallas Journal _ Dallas, Tex. 476 

WFAB Carl F. Weese. _ _ Syracuse, N. Y. 234 

WFAF H. C. Spratley Badle Ce Poughkeepsie, N. Y. 360 

WFAH Electrlo Supply Co _ Port Arthur. Tex. 236 

WFAJ Hi-Grade Wireless Instrument Co. Ashevllle, N. C. 360 

WFAM Times Publishing Co _ St. Cloud. Minn. 360 

WFAN Hutchinson Electrlo Service Co. Hutchinson. Minn. 360 

WFAQ Missouri Wesleyan College - - Cameron, Mo. 360 

WFAT New Columbus CoUege...- - ....Sioux Falls, S. Dak. 258 

WFAV University of Nebraska, Department of Electrical Engineering 

_ _ _ Lincoln. Nebr. 275 

WFI Strawbridge & Clothier. Philadelphia. Pa. 395 

WGAL Lancaster Electrlo Supply & Construction Co Lancaster, Pa. 243 

WGAN Cecil B. Lloyd _ _ Pensacola. Fla. 360 

WGAQ Glenwood Badio Corp. (W. G. Patterson) Shreveport, La. 360 

WGAW Ernest C. Albright Altoona. Pa. 261 

WGAY Northwestern Radio Ce Madison. Wis. 360 

WGAZ South Bend Tribune. _ South Bend, Ind. 360 

WGI 
WGL 
WGR 
WGV 
WGY 
WHA 



American Radio & Research Corp Medford Hillside, Mass. 360 

Thomas F. J. Howlett _ _ Philadelphia. Pa. 360 



Federal Telephone & Telegraph Co Buffalo, N. Y. 319 

Interstate Electric Co - _.._ New Orleans, La. 242 

Genera! Electrlo Co Schenectady, N. Y. 380 

University of Wlsconsln.. 



WHAA State University of Iowa.. 



... Madison. Wis. 360 

Iowa City. Iowa 283 

WHAB Clark W. Thompson. Galveston, Tex. 360 

WHAD Marquette University —Milwaukee, Wis. 280 

WHAG University of Cincinnati _ Cincinnati. Ohio 222 

WHAH Hafer Supply Co. Joplln. Mo. 283 

WHAK Roberts Hardware Co _ Clarkshurg, W. Va. 258 

WHAM University of Rochester (Eastman School of Music) Rochester. N. Y. 233 

WHAP Otta & Kuhns _ Decatur, 111. 360 

WHAR Paramount Radio & Electric Co. (W. H. A. Pulus) 

- Atlantic City, N. J. 231 

WHAS Courier- Journal & Louisville Times LouisvUf->, Kv. 400 

WHAV Wilmington Electrical Specialty Co. Wilmington. Del. 360 

WHAZ Rensselaer Polytechnic Institute Troy. YJ. Y. 380 

WHB Sweeney School Co.— _ Kansas City. Mo. 411 

WHK Radtovox Co. (Warren R. Cox) Cleveland. Ohio 360 

WHN George Schubel New York. N. Y. 360 

WIAB Joslyn Automobile C»..._ _ _ Rockford, ni. 252 

WIAC Galveston Tribune - Galveston. Tex. 360 

WIAD Howard R. Miller...- Ocean City. N. J. 254 

WIAF Gustav A. DoCortln.— New Orleans. La. 234 

WIAH Continental Radie & Mfg. Co _ Newton. Inwa 258 

WIAI Hear Stores Co Springfield, Mo. 252 

WIAJ Fox River Valley Radio Supply Co. (Qulnn Bros.) Neenah, Wis. 224 

WIAK Journal- Stockman Co Omaha, Nebr. 278 

WIAO School ef Engineering of Milwaukee .Milwaukee, Wis. 360 

WIAQ Chronicle PubUshlng Co _ Marion. Ind. 226 

WIAR Paducah Evening Sun. Paducah. Ky. 360 

WIAS Home Electric Co.— _ Burlington, Iowa 360 

WIAT Leon T. NoeL - Tarkio, Mo. 360 



WIAU American Trust & Savings Bank _ 

W1K K. & L. Electric Co. (Herbert F. Kelso 



Xe Mars, Iowa 360 

Kelso and Hunter J. Loliman) 

McKeesport, Pa. 234 

— Washington, D. C. 3G0 

-Philadelphia, Pa. 509 



W !d Continental Electric Supply Co.... 

WIP Gimbel Brothers . 

W-JAB American Electric Co.. 



Press Publishing Co.... 
WJAG Norfolk Dailv News 

WJAK Clifford L. White"" 

WJAM D. M. Perham 

WJAN Peoria Star _ ' 

WJAQ Capper Publications-""'" 



Muncie, Ind. 360 

.Norfolk, Nebr. 283 

Greentown, Ind. 254 

Cedar Baplds, Iowa 268 

— .Peoria, 111. 280 

..Topeka, Kans. 360 



w.a£ t?» „ 0utl , et S°: , < J - Samuels & Bro.) 

w!a? ^"sburgh Radio Supply House 

ff^ A ! Kelly-Vawter Jewelry Co 

WJAX Union Trust Co 

WJAZ Chicago Radio Laboratory.'".'"'- 

Wj H W Cha p d Bo Ter H ° We " : — GranviUe". ' Ohio 229 

<v t lioyer — — _ H;»hin«™ t> r. nit 



Providence. B. I. 360 

—Pittsburgh, Pa. 360 

Marshall, Mo. 360 

-Cleveland, Ohio 390 

..Chicago, 111. 448 



vm ^^^^'^^^''^^^"c.zz:::^^^, §. £ fg 



R. C. A 

WJZ R. C. A 

WKAA H. F. Paar..... '"""" 

WKAD Chas. Looff (Crescent Park)., 

KJJ w - S. Radio Supply Co.... 

,„ S A £ United Battery Service Co.... 

WKAP Dutee W. Flint- 



New York. N. Y. 405 
New York. N. Y. 455 



Yf!S A S Radio Corp. of Porto Rlco... 

... >?:? Michigan Agriculture College 

W S A ?, L - E - Lines M "sic Co. 

WKAV Laconia Radio Club 

WKAW Turner Cycle Co... 

WKAY Brenau College.... 

WKY WKY Radio Shop. 



Cedar Baplds. Iowa 268 

East Providence. B. I. 240 

Wichita Falls. Tex. 360 

Montgomery, Ala. 22S 

— Cranston, R. I. 360 



5X. LA 2 Cutting & Washington "Radio" Corp.- 

WLAH Samuel Woodworth 

JJJf-AJ Waco Electrical Supply Co.'.-"— '.'.".'.'.'. 

,w. LA . K Vermont Farm Machine Corp 

WLAL Naylor Electrical Co 

WLAN Putnam Hardware Co. '_'.""' 

WLAP W. V. Jordon 

WLAQ Arthur E. Schilling 



— San Juan, P. R. 360 

—Bast Lansing, Mich. 280 

Springfield, Mo. 360 

.Laconia, N. H. 254 

Beloit, Wis. 242 

Gainesville, Ga, 280 

— - - Oklahoma, Okla. 360 

Minneapolis, Minn. 417 

Syracuse, N. Y. 234 

— Waco, Tex. 360 

JJeUows Falls, Vt. 360 

TuBla, Okla. 360 

Houlton, Me. 283 

-Louisville, Ky. 360 

Kalamazoo. Mich 283 

-Burlington. Iowa 360 



WLAT Badio and Specialty"c"o! 

WLAW Pon>i T1en? 1 ' Swv ^~, Pensacola. FlaT 254 

vui"«I7 X . "*$»■■■ City of New York- New York N Y iSa 

WLAX Putnam Electric Co. (Greencastle Community Broadcasting Station) 

WMAJ Drovers Telegram Co ~ --Lincoln. Nebr. 254 

WMA.< Norton 3 2*3SSSta£ZZZ l^klln% ^ g! 

WMAL Trenton Hardware Co ZZZZ ~~ ~ "Trenton ^i T - Itn 

KKS? SSfc ^arlery « e --^===8l££L "ohfe 

WMAQ Chicago Dail™ News ■£'I t ?°' ?*• 248 

WMAV Alabama Polytechnic JSttut'eZZZZZZZZ 'Auourn ' Ala! 250 

SJz Mcr^ i &rs^^f! n -^ h ==fjg&. i£ 

wmh '^;™ ,a ^tt boo 

s£ D f^£^ i= ^^ sat s 

WNAM Ideai AppS us" Co """ T&53& H flf IS 

EBa? wS^one™ 6 ^ ™ 

WNAO Charleston l£*£ g Vw;T";i ~ ~ Springfield. Ohio 231 

WNAR C ha a St Rhod^.-..- 1 - * C ° " ^""buTw S 'm°' IS? 

WNAS Texas Radio Corp. & "Austo "staissn^ZZIZZ Austin "x §80 

WOAA d?"^?^ 3.3 

wua A mU W r- f Co rd L.ZZZZ.Z7 ATd ^lZ ° 0h ? HI 

woae Midland B #Sr & Eiectrio "'corp'zz'.zz::zzz:::sig-ou^?y a ; g h w '2 | 8 

WO A I ^ r an gom C m &Wirg5ZZZ .-.Fremont^ Neb, 360 

JK2.! 3 . Al" 1 "" Theater (Belvidero Amusement Co.) 

WO AH Palmetto Radio Corp. 

WOAI Southern Equipment Co _ 

WO A J Ervins Electrical Co.... 



— Belvidere. 111. 224 

Charleston, S. C. 360 

.San Antonio, Tex. 383 

- —Parsons. Kans. 258 

wn A b ^!'!i m ^_. W l 00 '. l3 :--i--v-.--.- -■-= —Webster Groves. Mo. 229 



WOAN Vaughn Conservatory of Music ( James" b.~Taughnj 

WOAO Lyradion Mfg. Co 

WOAP Kalamazoo College 

WOAQ Portsmouth Klwanls Club. 



..Trenton. N. J. 240 
..Davenport, Iowa 484 
..Ames, Iowa 360 



Lawrenceburg, Tenn. 360 

...Mlshawaka, Ind. 360 

.Kalamazoo, Mich. 240 

Portsmouth, Va. 360 

wSl? 5 en P\F- I' undsk °w._— _...._ Kenosha. Wis. 229 

wSaT/ ? J oyd M - F am , p ;; V-X Wilmington. DeL 360 

WOAv Pennsylvania National Guard. 2d Battalion. 112th Infantry 

wnav ^ 00 ? men v° f w th ,°- WorIi - Omahf. rl °Ne P br. 526 

WOAX Franklyn J. Wolff 

WOC Palmer School of Chiropractic.- 

WO I Iowa State College 

wnn £i n ° w Uff C ,° —ZZZZ. Pine Bluff.' ArkT 360 

wn2 w hn . W"" 1 ™ 1 "''; - Philadelphia. Pa. 509 

WOQ Western Radio Co Kansas City. Mo. 360 

WOR L. Bamberger & Co Newark N J 405 

.„2?o Ml3sou , ri State Marketing Bureau _ Jefferson City. ' Mo! 441 

wda? £™ n , s y lvanl £ S'ate CoUege _ state College. Pa. 283 

wd A £ vl?, naldS0 . n ?, adl< L Co "; ;■-;;--, Okmulgee. Okla. 360 

,V^ A , Wisconsin Department of Markets _ _ Waupaca, Wis. 360 

J;,o A ^ £ onUtt i e , Eadl ? Corp _ New Haven. Conn. 268 

JXo A< X ,,,r,h Uakota Agricultural College Agricultural College. N. Dale. 360 

,v!E A h Superior Badio & Telep. Equipment Co. Columbus, Ohio 288 

WPAM Auerbach & Guettel , ;i_: _ Topeka Kans 360 

!^E A ^ Theodore D. Phillips Winchester. Ky! 360 

JXS A S 9™^ "ales & Engineering Co _ ..Jrostburg, Md. 360 

WPAT St. Patricks Cathedral— _. _ J]] Pa^o Tex 360 

wE A i/ Concordia College... __ iioorhead. ' Minn! 360 

X^E AZ J £ hn K - £ mh <Dr ' ) Charleston. W. Va. 273 

JXE?. Nusawg Poultry Farm New Lebanon, Ohio 234 

JX2 AA £ oracB A. Beale ' * T - J?arkersburg, Pa. 860 

u,2«£ ^,n.. B „ G <f, h ••■"••-•"• — ■ • - - -Amarillo. Tex. 360 

WQAD Whitall Electric Co Waterbury. Conn. 242 

WQAE Moore Radio News Station (Edmund B. Moore) Springfield Vt 279 

W ,2 A f, Sar.duBky Register^ — . Sandusky. ' Ohio 240 

WUAH Brock- Anderson Electrical Engineering Co Lexington Ky 254 

WftAL Coles County Telep. and Telog. Co. Mattoon 111 258 

WQAM Electrical Equipment Co. -Miami Fla' 360 



46 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



WITH 





Duostat 

The Premier Electric Co., Chicago, 
recently announced a new and unusual 
apparatus. This new instrument is 
called the "Duostat" — so named because 
it does the work of two Rheostats. The 
manufacturers claim for it many unusual 
features. The windings are independent 
of one another. Each operates one tube. 
Simplifies wiring. The base is Bakelight 
moulded, dial silver etched, winding 
"Nichrome" wire. It is made for all 
types of tubes. Greatly simplifies installa- 
tion. Drill one hole, fasten to panel with 
nut supplied, and Presto — you have a 
finished job for any 2 stage amplifier. 



Liberty Audio Transformer 

The Liberty Transformer is very neatly 
encased in nickled brass with a top of 
molded condensite. All binding posts 
are nickle and plainly marked as to 
terminals. The entire instrument is 
small in size, the form being upright rath- 
er than horizontal. The transformer 
takes up a space of two and one-half by 
one and three-fourths inches of panel or 
base space and is strongly constructed. 
It has a ratio of five to one, which is suf- 
ficient for all needs in the average set not 
calling for a special high ratio winding. 

The transformer proper is well-made 
of good Swedish steel with the windings 
well insulated and there is not the least 
chance of a break or short-circuit due to 
wires being exposed as the entire trans- 
former is enclosed and no wires can be 
reached by any means. 

The people manufacturing this trans- 
former, by enclosing the transformer in a 
metallic case, have overcome inter- 
coupling or magnetic coupling between 
stages, causing howls and shrieks. It is 
manufactured by the Liberty Transform- 
er Company, Inc., Chicago, 111. 



The Willard Storage Battery Com- 
pany, Cleveland, 0., publishes a monthly 
quality organ, "The Connector." The 
publication presents fiction, trade news, 
trade suggestions, news of the com- 
pany's already famous broadcasting 
station, WTAM, and excellent illustra- 
tions. 



Condenser Construction 

A proper soldering connection for a 
Fixed Condenser has long been the desire 
of all manufacturers of radio sets as well 
as amateurs who build their own. 

It is, of course, comparatively easy to 
solder one connection to each terminal 
of every good Mica Condenser. But the 
task of making 4, 3, or even 2 clean 
connections to a Fixed Condenser has 
always resulted in a very messy job. 

With an evident realization of the im- 
portance to clear-toned radio reception, 
of affording the best possible soldered 
connections and neatly soldered joints, 
the CHAS. FRESHMAN CO., of New 




York City have made a radical improve- 
ment in the design of all capacities of 
their Tested Noiseless Mica Condensers, 
which should prove a boon to manu- 
facturers and radio enthusiasts who 
build and tinker with their own outfits. 

A lug of special construction is riveted 
by means of an eyelet to each terminal 
of the Mica Condenser. The lug is so 
designed that three or more different 
wires may be soldered to it, giving 
exceptionally good contact and allow- 
ing right-angle bends. The lug is 
equipped with three grooves, permitting 
the wires to be laid properly, and held 
in place while being soldered. 

Another most important advantage 
is that in wiring a set the connection can 
be made temporary without soldering. 
All that is necessary is to lay the wires 
in the lugs which are so constructed 
that they can be made to hold the wires 
without soldering by merely bending 
over the sides of the grooves to form a 
contact with the wire. In this way the 
circuit can be tested and varied so as to 
give the most efficient results. When 
this is attained the connections are then 
soldered. 

The accompanying illustrations show 
several methods in which the wires may 
be laid through the grooves in the lug, 
allowing bends of various kinds. 



In order to assist users of the Bremer- 
Tully Vernier Tuning Unit in getting 
the most out of that instrument the 
Bremer-Tully Manufacturing Co. has 
issued a booklet "Better Tuning." 



The pamphlet contains some interesting 
photographic illustrations of assembled 
circuits and several diagrams. The 
Bremer-Tully Mfg. Co., 532 Canal Street, 
Chicago, places a price of ten cents on 
the booklet, which is valuable to the 
radio fan, whether he uses Bremer- 
Tully products or not. 



The Western Coil & Electrical Co., 
Racine, Wis., favors us with circulars 
presenting facts about two outfits pro- 
duced by that company. The Radiodyne 
Type W C 10, is one of the receivers 
described. Superior sensitiveness is 
claimed for this six-tube outfit. Dry 
cells or storage batteries may be used. 
There are only two adjustments. There 
is a third knob for compensating for 
long or short balancing wires. The 
receiver is of the compound circuit 
type and requires nothing more than 
a twenty or thirty foot wire for balancing 
purposes. This wire may be thrown 
on the floor or strung up behind the 
picture moulding of any room, or 
strung up in the attic. No outside 
antenna is necessary. The outfit is 
enclosed in solid mahogany rub finish. 
It weighs 14 pounds and is priced at 
$150, exclusive of tubes. 

The same company produces the 
W C-5, which receives messages within 
a radius of 2,000 miles and is priced 
at $80. It is a four-tube circuit. In 
order to make it super-sensitive one 
stage of tuned radio frequency ampli- 
fication is employed ahead of the de- 
tector. It works well with an indoor 
antenna or without a high or expensive 
outdoor aerial. 



The rapidly increasing number of 
radio experimenters and receiver con- 
structors has created a growing demand 
for convenient tools with which to 
make and assemble sets. Among the 
manufacturers who specialize in pro- 
ducing such tools is the Simon & Skid- 
more Mfg. Co., Santa Ana, California. 
They are makers of the Simore Light- 
ning Change Tools. Their products 
include, squares, magazine screw drivers, 
containing three tools, and a magazine 
tool that contains knife blade and two 
screw drivers. 



Mahoganite 

The American Hard Rubber Company 
asks that the following be published: 

"Our attention has been directed to 
the fact that certain manufacturers of 
radio materials and parts have recently 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



47 



Complete Corrected List of U. S. and Canadian 

Broadcasting Stations 



WQAN 

WQAO 

WQAQ 

WQAS 

WOAV 

WQAW 

WQAX 

WRAA 

WRAD 

WRAF 

WRAH 

WRAL 

WRAM 

WRAN 

WRAO 

WRAV 

WRAW 

WRAX 

WRAY 

WRAZ 

WRC 

WRK 

WRL 

WRM 

WRR 

WRW 

WSAB 

WSAC 
W8AD 
WSAG 
WSAH 
WSAI 
WSAJ 
WSAL 
W8AN 
WSAR 



Seranton Times.. 

Calvary Baptist Churoh... 



_ Seranton. Pa. 280 

.New York. N. T. 360 

Abilene Daily Reporter (West Teias Badio Co.) Abilene, Tex. 360 

_ Lowell, Mass. 266 

Greenville, S. C. 258 

Washington, D. C. 236 

-Peoria. IU. 360 

_ Houston, Tex. 360 



Prince-Walter Co 

Huntington & Guerry (Inc.). 

Catholic University 

Badio Equipment Co. 

Bice Institute... 



Taylor Badio Shop (G. L. Taylor) Marion, Bans. 248 

The Badio Club (Ino) Laporte, Ind. 224 

Stanley N. Bead. - — Providence. B. I. 231 

Northern States Power Co. _ -...St. Croix Falls, Wis. 248 

Lombard College _ Galesburg, 111. 244 

Black Hawk Electrical Co _ - Waterloo. Iowa 236 

Badio Service Co St. Louis, Mo. 360 

Antloch College Yellow Springs, Ohio 360 

Avenue Badio Shop (Horace D. Good) Beading, Pa. 238 

Flaxon's Garage Gloucester City, N. J. 268 

Badio Sales Corp - Seranton, Pa. 280 

Badio Shop of Newark (Herman Lublnsky) Newark, N. J. 233 

Badio Corporation of America — _ Washington. D. C. 469 

Doron Bros. Electric Co. _ Hamilton. Ohio 360 

Union College Schenectady. N. Y. 360 

University of Illinois _ _ Urbana, HI. 360 

City of Dallas (police and Are signal department) Dallas, Tex. 360 

Tarrytown Badio Besearch Laboratory (Koenlg Bros.) 

Tarrytown. N. Y. 273 

Southeast Missouri State Teachers College. —.Cape Girardeau, Mo. 360 

Clemson Agricultural College. _ Clemson College, S. C. 360 

J. A. Foster Co - — Providence, B. I. 261 

City of St. Petersburg (Loren V. Davis) St. Petersburg, Fla. 244 

A. J. Leonard, jr _ _ _ _ Chicago. 111. 248 

United States Playing Cards Co.- Cincinnati. Ohio 309 

Grove City College _ _ _ _ _ Grove City, Pa. 360 

Franklin Electric Co..._ _.._ _ „ Brookville, Ind. 246 

Allentown Badio 01ub.._ -Allentown, Pa. 229 



Doughty & Welch Electrical Co. 



-Fall Blver. Mass. 254 



WSAT 

WSAW 

WSAX 

WSAY 

WSAZ 

WSB 

WSL 

WSY 

WTAB 

WTAC 

WTAF 

WTAG 

WTAH 

WTAJ 

WTAL 

WTAM 

WTAN 

WTAP 

WTAQ 

WTAR 

WTAS 

WTAT 

WTAU 

WTAW 

WTAX 

WTAY 

WTAZ 

WTQ 

WWA3 

WWAC 

WWAD 

WWAE 

WWAF 

WWAO 

WWI 

WWJ 

WVYL 



.Plalnvlew, Tex. 268 

..Canandalgua, N. Y. 27B 
..Chicago, 111. 268 



Donohoo-Ware Hardware Ce 

John J. Long, jr _ 

Chicago Badio Laboratory 

Irving Austin (Port Chester Chamber *f Commerce) Port Chester, N. Y. 23S 

Chas Electric Shop -. _.. .Pomeroy, Ohio 258 

Atlanta Journal. Atlanta, Ga. 429 

J. & M. Electric Ce _.Utlca. N. Y. 278 

Alabama Power Co.- _ Birmingham, Ala. 360 

Fall Blver Dally Herald Publishing Co. Jail Biver. Mass. 248 

Penn Traffic Co !. Johnstown, Pa. 860 

Louis J. Gallo — New Orleans, La. 242 

Kern Muslo Co ....Providence, B. I. 268 

Carmen Ferro. Belvidere. DX 236 

The Eadlo Shop Portland, Me. 236 

Toledo Badle & Eleotrio Co Toledo. Ohio 262 



Willard Storage Battery Co 

Orndorff Badio Shop 

Cambridge Badio A Electric 0* 

S. H. Van Gordon & Sen. 

Bellance Electrlo Co. 

Charles E. Erbsteln.. 



Cleveland. Ohio 3S9 

Mattoon. I1L 240 

Cambridge, 111. 242 

_ _...Osseo, Wis. 226 

--Norfolk, Va. 280 

.Elgin, IU. 275 

Edison Eleotrio Illuminating Co Boston, Mass. (portable) 244 

Buegg Battery & Electrlo Co. _: Tecumseh, Nebr. 860 

Agricultural & Mechanical College of Texas. College Station, Tex. 280 

Williams Hardware Co Streator. 111. 231 

Iodar-Oak Leaves Broadcasting Station. Oak Park, HI. 226 

Thomas J. McGulre.— _ Xambertvllle, N. J. 283 

Kansas State Agricultural College. Manhattan, Kans. 485 

Hoenlg, Swern & Co. (John Basmussen) Trenton, N. J. 228 

Sanger Bros Waco, Tex. 868 

Wright & Wright (Inc.) Philadelphia, Pa. 860 

Alamo Dance Hall, L. J. Crowley Joliet, 111. 227 

Galvin Badio Supply Co. Camden. N. J. 2S8 



Michigan College of Mines 

Ford Motor Co.. 



Detroit News (Evening News Assn.) 

Loyola University .,.,__,. 



...Houghton, Mleh...„244 

...Dearborn, Mloh. 278 

-Detroit. Mich. 517 



...New Orleans, La. 288 



Canadian Stations 



CFAC Western Badio Co., Ltd., 
CFCA Toronto Star 



.._...™.....„„ Calgary, Alta. 430 

_ .Toronto. Ont. 400 

Montreal, P. Q. 

Abltibl Power & Paper Co. Ltd Iroquois Falls. Ont. 



CFCF Marconi Co. _ 

CFCH 

CFCI 

CFCJ 

CFCK 

CFCL 

CFCN 

CFCO 

CFCW 

CFQC 

CFUC 

CHCB 

CHCD 

CHCE 



-Vancouver, B. C. 



W. W. Grant Eadlo, Ltd... 



440 
400 
410 

Quebec, P. Q. 410 

Edmonton, Alta 410 

Victoria, B. C. 400 

Calgary, Alta 440 

Bellevue. P. Q. 450 

._ London, Ont. 420 

—Saskatoon, Sask. 400 

_ Montreal, P. Q. 400 

Calgary Alta. 410 

— Quebec, P. Q. 410 

.Victoria, B. C. 400 



CHCL 

CHYC 

CJCA 

CJCD 

CJCE 

CJCI 

CJCN 

CJCX 

CJGC 

CISC 

CKAC 

CKCD 

CKCE 

CKCK 

CKOC 

CKY 



Canadian Northern Elee... 

Edmonton Journal, Ltd 

T. Eaten Co 

Vancouver Sun- 



McLean, Holt & Co., Ltd.. 
Simmons, Agnew & Co 



London Free Press.. 

Evenlng Telegram 

La Presse... 



Vancouver Dally Province... 
Can. Ind. Telephone Co.... 
Leader Publishing Co 



Wentworth Badio Supply Co._ 



•.■.-Vancouver, B. C. 440 

...Montreal. P. Q. 410 

-Edmonton, Alta. 480 

._ Toronto. Ont. 418 

.—.Vancouver, B. C. 420 

St. John. N. B. 400 

Toronto. Ont. 410 

Olds. Alta. 400 

—London. Ont. 430 

.Toronto, Ont. 430 

Montreal. P. Q. 430 

Vancouver, B. C. 410 

Toronto, Ont. 450 

_ Beglna. Sask. 420 

..Hamilton, Ont. 410 



...Winnipeg, Manitoba 450 



started to use the name 'Mahoganite' 
on some of their devices. This name is 
one of our trademarks for radio material 
and for panels, dials and other radio 
parts. Realizing that the unauthorized 
use of this name by others in the past 
may have been inadvertent, we are taking 
this occasion to bring to the notice of the 
trade the fact that we own the exclusive 
right to the use of the name 'Mahog- 
anite' for radio materials and parts and 
that we shall look upon as an infringer 
anyone who uses this name upon similar 
products." 



An attractive booklet is issued by the 
Atlantic Radio Electric Co., 308 South 
Clark Street, Chicago. The pamphlet 
contains illustrations and descriptions 
of the well-known "Bestone" radio 
merchandise. This line is a complete 
one, including everything from complete 
tube and crystal sets to switchpoints, 
variocouplers, variometers, headsets, 
condensers, and transformers are partic- 
ularly well presented and attractively 
priced. 



New Grid Leak 

The Allen-Bradley Company, manu- 
facturers of the Universal Bradleystat 
and Bradleyometer, have added another 
item to their line of graphite disc radio 
products. 

The new device is an adjustable grid 
leak, known as the Bradleyleak, which 
was developed to meet the insistent 



demand for a high-grade, dependable 
grid leak. It is similar in external 
appearance to the Universal Bradley- 
stat and is equipped with an adjusting 
knob which conforms, in general design, 
with the approved tapered knob now 
used in most radio equipment and match- 
es perfectly with the adjusting knobs of 
the Bradleystat and Bradleyometer. 

The Bradleyleak can be adjusted 
between the limits of 250,000 ohms and 
10,000,000 ohms or, as usually stated, 
between one-fourth megohm and ten 
megohms. The entire range of grid leak 
resistance between these limits is instant- 
ly obtainable without noises, steps or 
jumps by simply turning the adjusting 
knob. It is a significant fact that all 
intermediate values of resistance can be 
accurately obtained at any time which 
is a feature not often found in many 
types of adjustable grid leaks. 

The base of the Bradleyleak is recessed 
to receive a small fixed condenser which 
is furnished as an extra attachment if 
desired. The grid condenser is accurate- 
ly adjusted to a capacity of 0.00025 
microfarads. 



"Battery Charger" 

{Continued, from page 28) 
directly to the alternating current mains 
and the secondary directly to the rectifier. 
The voltage of these toy transformers is 
usually adjustable, so that the rate of 
charging may be regulated by the con- 
trolling switch on the secondary of the 
transformer. This method will charge 
the battery faster, and is much more 
efficient. 



New Crosley Factory 

In order to meet the demand for Cros- 
ley-made radio receiving sets, Powel 
Crosley, Jr., president of the Crosley 
Manufacturing Company, has purchased 
the four-story factory building now oc- 
cupied by the Thomas J. Corcoran 
Lamp Company, on Colerain Avenue at 
Sassafras Street, in Camp Washington, 
Cincinnati. This real estate transaction 
involving more than $150,000, surely 
meets the question of whether the radio 
industry is an established business or a 
passing fad, for preparations are being 
made to manufacture nearly 5,000 radio 
receiving sets every day in this new 
plant which will be ready for occupancy 
by early spring. 

The large building will house, in addi- 
tion to the general offices, manufacturing 
and assembling departments of the 
Crosley radio products, the radio broad- 
casting station, WLW, which will have 
all of the latest improvements of this 
particular field in the radio world, mak- 
ing the station one of the finest in the 
world. 

There is a floor space of over 100,000 
square feet in this new four-story build- 
ing, as compared with 30,000 in the pres- 
ent Crosley factory, at Alfred and Col- 
erain, and this large space will be fully 
utilized with the manufacture of radio 
receiving apparatus. It is the intention 
of Mr. Crosley to manufacture radio 
parts in the present building and to 
use the new one for the making of the 
complete outfits. There is a B. & O. and 
Southwestern Railway company siding 
which goes to the plant, facilitating the 
shipping of the raw and finished products. 



48 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



ERLA BLUE PRINTS 

Erla Receivers out-distance other sets with an almost 
unbelievable volume and a naturalness that cannot be 
distinguished from the source of reception. 

This is the famous Erla Reflex Hook-up. Less than 
one year old — but has taken the entire nation by storm. 
Every listener-in raves about it and wants a set of his 
own immediately. 

So easy to construct that anyone who can handle a 
screw driver can build the set complete in a sur- 
prisingly short time — about 1 1-2 hours. Everything 
is so simple and easy. 

NO SOLDERING WHATEVER— ONLY A 
SCREW DRIVER NEEDED. 

The results from the Erla 3 tube is naturalness itself and can- 
not be improved upon. Actual size working diagrams make 
every thing simple and easy. Every piece of apparatus and 
every wire is pictured in its exact place — every article needed 
is listed on the diagrams. 

Diagrams sent same day your order is received. 
Send P. O. or Express Money Order or Bank draft 
or Bank Cashier's check. Do not send stamps or 
personal checks. 

Erla Hook-up Diagram Prices 

3 sheets for making 1 tube set 25c 
3 sheets for making 2 tube set 35c 
3 sheets for making 3 tube set 50c 

Frank D. Pearne 

Sole Distributor of Erla Diagrams for U. S. and Canada 
829 Waveland Avenue, Chicago, III. 

Dealers, Write for Quantity Prices 



Reinartz Adap- 
tions 

( Continued from page 6.) 
Queer as it may seem, the use of radio 
frequency amplification with the Rein- 
artz circuit is not always according to 
"Hoyle," but if care is exercised in con- 
structing the set, the results are partic- 
ularly gratifying. 

The reversal of the reactance coil 
marked "x" in the diagram is often nec- 
essary when a second tube is added for 
radio amplification, but is a matter of ex- 
periment. One experimenter winds the 
entire Reinartz inductance on a 3-inch 
cardboard tube according to the regular 
specifications, but instead of placing the 
plate coil winding "x" alongside of the 
antenna coil, winds it on a separate small- 
er tube and inserts it inside of the larger 
coil. The winding should be in reverse 
direction to the larger antenna grid coil. 
The circuit shown makes use of the tuned 
impedance type of radio amplification, 
which is highly efficient in covering a 
large band of waves. 

Figure 4 shows the method used by an 
English amateur who uses the Reinartz 
hookup for obtaining the best results 
with radio frequency amplification. With 
the exception of a few changes in con- 
stants it is practically the same as that of 
Figure 3. He, however, uses only 1 B 
battery, and gives the following specifica- 
tions for the winding of the coils. 

The entire coil is wound with No. 22 
DCC on a 3-inch tube. Ten turns are 
first wound with taps at every turn. The 
tenth tap connects to the potentiometer 
and ground. Twenty additional turns 
are then wound and a tap is taken off 
for the grid switch, then fifteen more are 
wound, and last the coil is completed with 
fifteen more, making the total number of 
turns from the tenth tap of the antenna 
coil to the last grid tap fifty turns. 

The plate coil should consist of 40 
turns of the same size wire wound on a 
smaller tube, in the opposite direction to 
the antenna-grid coil. This smaller tube 
is inserted at the antenna end of the 
larger coil, as mentioned before. 

The auto transformer coupling arrange- 
ment consisting of 36 turns of No. 16 wire 
on a 3 inch tube should be placed at right 
angles to the grid inductance, and as far 
away as possible to offset any inductive 
effects which might exist. 

If an audio frequency amplifier is 
added, it is necessary to leave the phones 
connected in the plate circuit of the de- 
tector, in order that the phone resistance 
may act as an impendance. 

The writer hopes that these suggestions 
may develop some successful long dis- 
tance receptions with two tube Reinartz 
sets, and would be pleased to hear from 
fans with regard to any new kinks or 
wrinkles they may chance to discover in 
working out these circuits. 



Don't Fail to renew your 
subscription ! 



^ C" 1 ' ' " S o 1 m jC '■ - JP 



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Here's How! 

Having gained approximately 35,000 in four months and having added materially 
to the quantity, quality and appearance of our magazine we have not increased the 
subscription price, although we are told by thousands of fans that our periodical pre- 
sents the best isometric drawings and wiring diagrams and the most timely, instruc- 
tive articles available anywhere. You, yourself have just read this number of Radio 
Age. We are printing magazines like this every thirty days. 

You cannot always get Radio Age on the news stand. Dealers sell out in a hurry. 
As we were about to go to press for this issue we were still receiving telegrams and 
letters from dealers asking for new supplies of the January issue. (Did you read that 
now famous wave-trap article on tuning out interference — four pages of information 
with ten crystal-clear illustrations?) If you are a subscriber we insure delivery each 
month. 

How about that 50 cents? 

That's where the Radio Age Annual for 1924 comes in. You get this fine col- 
lection of all the standard hook-ups, with page after page of the best Radio Age 
drawings and the clearest instructions on how to build any standard set together 
with a year's subscription to Radio Age for only $3.00. We have put a rock bottom 
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NOT a collection of difficult diagrams with scanty scraps of instructions 
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that will tell you all you need to know to build ANY KIND OF A 

Standard Receiver at home. 

Picture-diagrams (isometric) that show even the radio novice where to place 
the parts and how to connect the wires. These drawings are copyrighted 
and you cannot get them elsewhere than in this book. 

Everything is explained and illustra?ed, from the crystal set to the super- 
heterodyne. It is an up-to-the-minute guide for the radio experimenter 
who wants the oldest, the best and THE LATEST. 



Simple Crystal Set 

Long Distance Crystal Set 

Your First Tube Set 

Kopprasch Circuit 

Erla Reflex 

Kaufman 

Grimes Inverse Duplex 

Two Stage Amplifier 

Junior Heterodyne 

One Tube with Loop Aerial 

Wave Trap, Filter, Eliminator 

Loading Coils 

Transformers 

Code Instruction 



Reinartz 

Hop-wood 

Haynes 

Cockaday 

Neutrodyne 

Three-circuit Tuner 

Super-Heterodyne 

Simple Radio Frequency 

Ultra Audion 

Rosenbloom 

Push-Pull Amplifier 

Portable Reinartz 

Wave-Meters 

Two-Circuit Crystal 



THE foregoing is only a partial list of the good things in this book. 
You can learn the wireless code, or make an interference preventer; 
in fact, turn your workbench into a complete home laboratory. 

Hundreds Sold Before the Presses Started! First 5000 Ready Now! 
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For 1924 

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Radio dealers, news dealers and booksellers, write for price* 





MARCH 

1924 




In This Number 

Kopprasch Circuit — Isometric drawing — Fully -described. 
Super Heterodyne — Another fine Pearne article. Winding 
Heterodyne Transformers — A Rathbun feature. The 
Simplifigon Receiver — Text and drawings by Anderson. 
Complete corrected list of Broadcasting stations. More 
good hooktq 



\JOet Our Hook-ups Be your Guide 



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rm 



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TO) 



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wrote us on receiving his 



RADIO AGE ANNUAL 



19 24 EDITION, ILLUSTRATED 



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CORES of busy fans have taken the time from their work benches 
to write us that they are finding the Radio Age Annual just the 
thing they have been looking for. It shows them where the parts 
go and how and where the wires are connected — and why. It gives them 
picture diagrams that are much easier to understand than blue prints, 
far superior to the old-fashioned iviring diagrams that to the beginner 
are only a conglomeration of curves, corners and arrows. You can only 
gel these isometric drawings in Radio Age Annual. Below is a list o 
standard receivers and equipment which this hook shows you how to make. 




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Simple Crystal Set 

Long Distance Crystal Set 

Your First Tube Set 

Kopprasch Circuit 

Erla Reflex 

Kaufman 

Grimes Inverse Duplex 

Two Stage Amplifier 

Junior Heterodyne 

One Tube with Loop Aerial 

Wave Trap, Filler. Eliminator 

Loading Coils 

Transformers 

Code Instruction 



Reinartz 

Hopwood 

Haynes 

Cockaday 

Neutrodyne 

Three-Circuit Tuner 

Super-Heterodyne 

Simple Radio Frequency 

Ultra A udion 

Rosenbloom 

Push-Pull Amplifier 

Portable Reinartz 

Wave-Meters 

Two-Circuit Crystal 



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E ^^^g^g g^z^^g^sasags^g^^^^^^^z^gzz^z^^^sa^g^^^^g^E^zzg^ggzz agz^^z^^ ^gz zzzzg^ m^^^zz^a^ a 



The Heart of the "Long 45" Circuit 
is the long 45 Tuner 



The one-tube sensation of the 
year — inexpensive, practical 




REGISTERED 



JT'HE "Long U5" Tuner — devised for one tube, 
inexpensive circuits to reach from coast to 
coast on the "Phones" and to give remarkable 
results on the "loud speakers." 



EN8ATI0M 



"T'HE "Long 45" tuner with its simple one tube 
circuit has created a furore in New York, 
Chicago and other large cities where it has been 
introduced. 

It is the most wonderful tuner and circuit 
devised by radio experts. 



ASK TO SEE IT AT YOUR RADIO DEALERS OR INQUIRE OF 




RADIO DIVISION DEPT. RA 

1319 MICHIGAN AVE., 

CHICAGO, ILLINOIS 



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RADIO AGE— "THE MAGAZINE OF THE HOUR" 



RADIO AGE 

The Magazine of the Hour 

Established March, 1922 



Volume 3 



MARCH, 1924 



Number 3 



CONTENTS 

Page 

Constructing the Superheterodyne 5 

By F. D. Pearne. 

How to Make a Simple Low Loss Tuner — 9 

By Felix Anderson. 

Junior Heterodyne Transformers 11 

By J. B. Raihbun. 

A Tuned Radio Frequency Amplifier .....13 

By J. A . Callanan. 

How to Make the Kopprasch Receiver 15 

By Felix Anderson. 
Adding Radio Frequency to the Variometer 

Set ...19 

Whistling Interference — Causes and Effect ..21 
By J. V.L. Hogan. 

A Simple Reflex Set 23 

Pickups and Hookups. 25 

By Our Readers. 

Troubleshooter Section.. __ 33 

What the Broadcasters Are Doing 37 

With the Manufacturers .40 

The Teledyne Circuit ...42 

Corrected List of U. S., Cuban and Cana- 
dian Stations 51 



Radio Age is published monthly by 
RADIO AGE, Inc. 

Publication office, Mount Morris, 111. 
Editorial and Advertising Offices, Boyce Building, 
500 N. Dearborn St., Chicago 

Frederick Smith, Editor 
Frank D. Pearne, Technical Editor 
M. B. Smith, Business Manager 
Louis L. Levy, Circulation Director 

Western Advertising Representatives 

BRUNS & MACDONALD 

First National Bank Building, Chicago 

Eastern Representatives 

E. V. HEVEY & COMPANY 

17 West 42nd Street, New York City 

Telephone, Longacre 1698 

Advertising forms close on the 15th of the month 
preceding date of issue 

Issued monthly. Vol. 3, No. 3 Subscription price $2.50 a year. 

Entered as second-class matter September 15, 1922, at the post office at Mount 

Morris, Illinois, under the act of March 3, 1879 



Copyright, 1924 by'_RADIO ACE, Inc. 



What Readers Teach Us. 

THOUSANDS of readers of 
RADIO AGE have written 
to us in the last sixty days 
ordering back copies of the maga- 
zine. Many of them wanted num- 
bers dated back in the early part 
of 1922. In fact our supply of many 
of the issues desired has been ex- 
hausted. Most of the letters have 
specified the particular article in 
the back number which the reader 
desired. 

Those letters, therefore, have 
been an education to the editor. 
He has learned that radio fans are 
more interested in some circuits 
than they are in others. He has 
ascertained what a majority of 
readers are striving to make, or to 
understand. 

The result of all these letters will 
be reflected in the coming issues of 
RADIO AGE. We have already 
responded to the information thus 
obtained by presenting particularly 
good articles on the Reinartz, the 
Kopprasch, the Four Circuit Tuner, 
the Single Tube, the Selective 
Crystal Detector, the Heterodyne 
and various other hookups. In 
this number will be found good 
drawings and helpful information 
relating to the Heterodyne, the 
Simplifigon Coil, the Kopprasch 
and other circuits in which we 
know the radio public is keenly 
interested. 

For those who were too late to 
obtain desired back numbers we 
have prepared a book called "Radio 
Age Annual for 1924," which con- 
tains a collection of the best hook- 
ups and drawings published in 
RADIO AGE. This book is being 
sold by the thousands because, 
like the magazine, it presents radio 
problems and solves them in a 
manner that is clear, accurate, 
comprehensive AND ORIGINAL. 



—Editor, RADIO AGE 



Eveready gives you the right battery 
for every radio use! 

EACH Eveready Radio Battery represents thirty years of battery 
building experience. Each Eveready Battery represents millions 
of dollars invested in men, methods and machinery. Overseeing 
Eveready production is the greatest battery laboratory known to 
science, where every particle of raw material is required to pass 
Eveready 's exacting tests. To insure Eveready serviceability, batches of 
Eveready Batteries are constantly being set aside for performance tests. 
And, finally, daily shipments keep dealers supplied with fresh Eveready 
Batteries, packed full of power. 

To be certain of battery satisfaction, insist on Eveready Radio 
Batteries — they last longer. 




EVEREADY 

Radio Batteries 



- they last longer 



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The radio dry cell triumphant 

For economical, satisfactory radio, light the filaments of 
your dry cell tubes with the Eveready Dry Cell Radio "A" 
Battery. Will unfailingly outlast any other at % ampere current. Full 
instructions for getting this Economical Eighth, on labels and in our 
booklets. This battery will exceed your expectations in economy and 
performance. 

Equal to all demands 

Power flows from your "B" Battery, power' that gives life to your 
headphones or loud speaker. Some tubes draw more "B" Battery current 
than others, but whatever the tube or tubes you use, Eveready "B" 
Batteries will give you maximum results. Eveready "B" Batteries are 
made in six sizes, for all possible uses. Always use the biggest possible 
battery, for it contains more energy in proportion to cost, and lasts longer. 

This battery is a wonder worker 

Eveready's biggest contribution to economical and more 
satisfying radio is the Eveready "C" Battery, a triple-use, 
universal battery. It will make the loud speaker respond 
with a new fullness and naturalness of tone, and save much 
money by making the "B" Battery last still longer. Connect 
it with the grids of audio frequency amplifiers and notice the 
big difference. Can also be used as an "A" Battery for 199' 
type tubes in portable sets, and as a "B"' Battery booster. 
Eveready Radio Battery No. 771 — use it! 

NATIONAL CARBON COMPANY, Inc., New York and San Francisco 

Headquarters for Radio Battery Information 

CANADIAN NATIONAL CARBON CO., Limited. Factory and Offices: Toronto, Ontario 

Informative and money-saving booklets on radio batteries sent free on request. If you have any radio battery problems, write 
to G. C. Furness, Manager, Radio Division, National Carbon Co., Inc., 202 Orton Street, Long Island City, N. Y. 

THE AIR IS FULL OF THINGS YOU SHOULDN'T MISS 





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RADIO AGE 

"THE MAGAZINE OF THE HOUR" 



M. B. Smith 

Business Manager 



A Monthly Publication 

Devoted to Practical 

Radio 



Frederick A. Smith 

Editor 



Constructing the Superheterodyne 

The Most Sensitive Receiver in the World 
By FRANK D. PEARNE 



THERE are many radio enthus- 
iasts who ask to know what is the 
best kind of a receiver to build, 
regardless of cost, the idea being to get 
the greatest possible reception. The 
answer to this question is the "Super- 
heterodyne." This circuit is without 
doubt, the most sensitive and best long- 
distance getter of all. This fact is con- 
ceded by most of the radio experts of this, 
and other countries and for the man who 
cares not for the cost but wants the 
best, it is always recommended. It may 
require more practice to learn just how to 
tune it and there are more controls 
necessary than those required in most 
receivers, but when properly constructed, 
one may feel sure that he can get any 
station which is on the air within a range 
of two or three thousand miles and they 
have been known to reach as far as seven 
thousand miles. 

How it Operates 
The current produced in the loop 
aerial by the cutting of the lines of 
force carried to it on the wave from the 
broadcast station will have the same 
frequency as that sent out by the trans- 
mitter. These frequencies from different 
broadcast stations will range from 500,- 
000 cycles of the 600 meter wave, to 
1,200,000 of the 250 meter waves, which 
are of course too high to be detected by 
the human ear. In the usual course of 
events this wave would appear as shown 
at i'A" in Figure 2. The changes which 
take place in the amplitude of this wave 
is really what produces the sound in the 




phones, or loud speaker. It must be 
understood that the frequency of the 
wave remains the same, but that sounds 
striking the diaphragm of the micro- 
phone at the broadcast station, merely 
change the height, or amplitude of the 
wave. An example of just how this 
change, or modulation of the wave takes 
place is shown in Figure 3. This is the 
modulation which occurs when the letter 



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WW A + B 



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eem current 



Figure 3. This curve shows how the 
transmitting station's wave is varied in 
amplitude when the letter "A" is spoken 
into the transmitter. 



ffRIODIC 

Louasp0VGR currm 



Figure 2. This illustration shows in 
chart form the action of the Super- Hetero- 
dyne receiver described herewith. At A, 
we have the incoming wave as radiated by 
some transmitting station. Upon these 
oscillations, oscillations generated by the 
oscillator tube of the set are superimposed. 
The local current is of slightly different 
frequency, as shown at B, and the combined 
frequencies A and B result in a so-called 
"beat" current shown at C. This beat 
current is sent through the radio frequency 
amplifiers and is tremendously amplified, 
effecting .a much greater current to be 
rectified by the detector than would ordi- 
narily be obtained. The detector permits 
the oscillations {or amplified beat current) 
to pass only in one direction, and the signal 
takes the form of the wave shown at D. The 
signal, in the form of a pulsating direct 
current shown at E, is then transposed 
into mechanical energy by the loud speaker. 

"A" pronounced as in "fathei" is spoken 
in front of the microphone. 

It will be noticed that the frequency 
remains unchanged, but the tops of the 
different oscillations are cut off according 
to the vibration of the microphone dia- 
phragm. Figure 4 shows the same 
modulated wave after it has been recti- 
fied by the detector. 

From this it will be plainly seen that the 
oscillations occur entirely too fast to 



affect the diaphragm of the receiver, but 
after they are rectified, as shown in 
Figure 4 it becomes a varying direct cur- 
rent, which varies according to the shape 
of the peak of the rectified current and 
this current being direct in its nature, 
will vary the diaphragm of the head 
phones, or loud speaker and cause it to 
reproduce the sounds produced in front 
of the microphone. 

Now, in order that signals, music, etc., 
may be heard from a great distance, it is 
necessary to amplify them, or build them 
up to a greater strength than that at 
which they are impressed upon the loop. 
This is best done before they are rectified 
for the reason that no distortion takes 
place when they are amplified in their 
original form, or rather at the frequencies 
which are too high to be heard by the ear. 
This is called radio frequency amplifica- 
tion and by its use the strength of the 
incoming signal may be built up to such 
an extent that signals which are entirely 
too weak to be heard with an ordinary 
detector alone are magnified to an enor- 
mous strength before they are rectified 
and brought down to audio frequency, oi 
in other words made audible in the 
phones. Here, however, is where the 
first serious difficulty is encountered. 
There are several methods of radio fre- 
quency amplification, the most popular 
being the transformer method. 

Every radio frequency transformer 
has what is known as a fundamental wave 
length of its own, which means that there 
is one particular frequency at which it 
will work at very high efficiency, this 
efficiency falling off rapidly as the fre- 
quency varies from the fundamental. 
Various methods of changing this funda- 
mental wavelength have been suggested, 
for the reason that so many different 
frequencies are used by broadcast sta- 




Figure 4. The same curve as illustrated 
in Figure 3, after being rectified by the 
detector tube of the set. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



m-357UQMS L+ 2f7UQA/S 



2 SoiQFX/NO- J-VG-S 



LP- 5 'WRAP OM 
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Figure 5. A sketch showing the construction and detail of the heart of the Super- Hetero dyne circuit. This is the oscillator unit , 
which consists of one 25 turn coil, and one 35 turn coil, wound side by side on the same form, and the coupling coil (L5) wound on a 
lube of smaller diameter placed inside of the larger. The unit is mounted by slotting two pieces of bakelite as shown and inserting the 
coils. The entire unit is then mounted upon a bakelite or hard rubber base, and is securely bolted together upon four legs. The two end 
pieces, acting as supports for the tubes, also serve the purpose of a mounting for the connectors. 



tions and in order that reception from any 
and all of them may be obtained at equal 
efficiency, it would be necessary to change 
this fundamental wavelength of the 
transformer to meet the particular fre- 
quency of the desired station. Such an 
arrangement is not very satisfactory 
as it is always found that one certain 
wavelength will be received much better 
than any other. 

How Heterodyne Works 
This is where the wonderful efficiency 
of the superhetero- 
dyne set solves the 
problem. Instead of 
varying the wave 
length of the radio 
frequency trans- 
formers the fre- 
quency at which 
they work most effi- 
ciently is ascertain- 
ed and the fre- 
q u e n c y of the 
incoming wave is 
changed to that par- 
ticular frequency, so 
that no matter what 
may be the length 
of the incoming 
wave, it is always 
the same frequency 



transformers and consequently they al- 
ways work at their greatest efficiency, 
regardless of the frequency of the in- 
coming wave. 

At first thought, it would seem that 
such an arrangement was impossible, but 
it can be accomplished by means of a 
local oscillator circuit which produces a 
frequency which may be varied at will. 
These local oscillations are super-imposed 
upon the incoming oscillations and the 
result of this combination is a "beat" 



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CONNECTION TOR Li 



CONNF-CTIOK POQ L- 




5 TCOIL (lUSlbE) 



Figure 6. This illustrates the method of making the connections for the inside and 
when it reaches the outside coils of the oscillator unit. The center lug is used for the inside (L5) ceil, and 
radio frequency the two outside lugs form the terminals for coils L3 and 4 respectively. 



wave which will have a frequency equal 
to the difference between the two. Be- 
cause of the fact that the frequency of the 
local oscillating circuit may be varied, 
a beat oscillation which has the same 
frequency as the fundamental frequency 
of the radio frequency transformers may 
be obtained, no matter what the fre- 
quency of the incoming wave may be. 

Thus it will be seen that the radio 
frequency transformers always operate at 
the same frequency, no matter what the 
frequency impress- 
ed upon the loop 
may be, and the 
result of such an 
arrangement is a 
highly efficient 
transformation sys- 
tem, building up 
the weak signals to 
such an extent that 
when they reach 
the detector they 
are rectified at great 
strength after which 
they may be again 
amplified at audio 
frequency to get 
any desired volume. 
By reference to 
Figure 2 it will be 
noted that "A" 
shows the oscilla- 



COVMe'a/OAl FOR L 4. 



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RADIO AGE— "THE MAGAZINE OF THE HOUR" 



tions of the incoming wave "B", shows the 
oscillations set up by the local oscillator, 
"C" is the resultant "beat" oscillations, 
"D" is the result of the beat oscillations 
when rectified by the detector and "E" 
shows the varying direct current which 
passes to the phones, or loud speaker. 

In the circuit shown in Figure 1 the 
loop is tuned by means of a 17-plate 
variable condenser and the incoming 
wave is amplified by passing through an 
amplifying tube before passing to the 
oscillator. A variometer is placed be- 
tween the plate of this tube and the oscil- 
lator coil. This variometer is used to 
control the regeneration. This oscillator 
coil consists of five turns of No. 22 
double silk covered wire, wound in the 
center of a bakelite tube 1 1-2 inches in 
diameter and 3 inches long. The other 
two oscillator coils are wound upon a 
bakelite tube 2 1-2 inches in diameter and 
3 inches long. The 5 turn coil is mounted 
inside of the tube carrying the two coils, 
by means of bakelite supports placed 
across the ends and slotted in the right 
places to allow the tubes to be held in 
their respective places when placed in 
the slots. 

Assembling Oscillator 

Figure 5 illustrates the method of 
assembling the oscillator. The 2 1-2 inch 
tube is wound with two coils, one having 
35 turns and the other 25 turns. These 
two coils are wound in the same direction, 
the second being spaced about one-eighth 



of an inch from the first. Bring all term- 
inals out inside of the tubes and connect 
the leads to clips which are mounted on 
the bakelite supports. Four brass legs 
are used as the main support of the 
oscillator. These are placed between the 
bakelite tube supports and the base as 
shown, and should be long enough to 
keep the coils of the oscillator at least 
one-half inch from the baseboard. A 
four-foot loop having 12 turns of wire 
No. 18 or larger will answer the purpose. 
This is wound in a solenoid form on four 
pieces of bakelite mounted on a frame 
which is made in the form of a cross. 
Stranded wire is to be preferred and the 
turns should be about one-half inch apart. 
A 17-plate variable condenser is shunted 
across the terminals of the loop as shown. 
The first tube, that is, the tube which 
precedes the oscillator is really a radio 
frequency amplifying tube, although some 
call it the first detector. This tube as 
well as all the rest with the exception of 
the detector tube should be either 
UV-201-A,-or C-301-A. 

The detector tube should be either a 
UV-200, or a C-300. The variometer 
may be any of the standard types on sale 
at the radio supply stores. This vari- 
ometer is connected between the plate 
of the first tube and the 5 turn coil of the 
oscillator. The other end of the coil is 
connected to the post on the first radio 
frequency transformer marked "P." A 
.001 M. F. fixed mica condenser is placed 
between the two outside coils of the 



oscillator and a 23-plate variable con- 
denser is connected across the two out- 
side terminals of these coils. This is 
used to tune the miniature transmitting 
station which is formed by the oscillator. 
The two outside terminals of these two 
coils are also connected to the grid and 
plate of the oscillator tube. The filament 
of this tube and the filament of the first 
tube are each controlled by a 25 ohm 
rheostat. From this point on, the circuit 
is the conventional radio frequency 
amplifier, detector, and two stage audio 
frequency circuit, all connections being 
plainly shown in Figure 1 and no difficul- 
ty should be experienced in connecting it 
up. The radio frequency transformers 
should have a wavelength of about 5000 
meters and if any difficulty is found in 
procuring them, they may be made 
according to the method described by 
John B. Rathbun in an article on trans- 
former construction in this issue. 

Tuning Hint 

In tuning, it will be found that if the 
first tube is tuned to an incoming wave 
and the condenser of the oscillator is 
adjusted so that oscillations of nearly 
the same frequency are set up, a beat note 
will be produced. If the oscillator is 
tuned to the same frequency as the in- 
coming wave, no beat note will be pro- 
duced. The oscillator is varied until 
the proper beat note frequency is obtained 
at which point the signal will be very 
strong. 




MOVIES INVADE RADIO 
Moving pictures were taken recently of two Chicago broadcasting stations in action. The above picture shows 
Norman Alley, of the International Newsreel, as he was "shooting" Jack Nelson, studio director of the Chicago 
Board of Trade Station, WDAP, in the Drake Hotel, Chicago. Moving pictures of this station and of Zenith-Edge- 
water Beach, WJAZ, are now being shown on silver sheets all over the country. 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 




RADIO AGE— "THE MAGAZINE OF THE HOUR" 



How to Make a Simple Low Loss Tuner 



IN THE course of their radio experi- 
ences, Radio Age readers have 
undoubtedly been afforded the pleas- 
ure of visiting the home of some fellow 
dial-twirler who possesses a receiver of 
the so called "haywire" type. 

He has also probably felt the pangs of 
jealousy when the list of stations heard 
on his receiver were compared with the 
haywire set, and to his chagrin found 
that the "haywire" set beat his by a 
mile. In all probability he will recall 
that he wondered how in the world that 
mass of radio stuff (usually spread out 
on a superannuated table) could pos- 
sibly work at all! 

The whole secret lies in the fact that 
the owner of the haywire receiver in 
building up the set without all the cus- 
tomary fancy cabinets, nickel plated 
switches and other hardware that go 



te&AL 



By FELIX ANDERSON 

Technical Assistant, Radio Age 

need it badly. Second, we want a tuner 
that will cover all the waves of the 
broadcasting stations, namely from 225 
to 546 meters. Third, a tuner that will 
not reradiate and interfere with the 
reception of our neighbors. Fourth, 
be simple and with a few major controls. 
Fifth, be of reasonable cost, and easily 
constructed. Sixth and last, be reliable 
so that when a station is once logged it 
can be heard at will upon properly adjust- 
ing the controls to the proper values. 

Resistance in Tuning Circuits 

To make a tuner that will tune sharply, 
we must make one that will have little 
or no resistance in the tuning circuits. 
Resistance in circuits is something that 
almost every builder has been "ducking." 
Tubes, needless controls, dizzy circuits 
and more amplification stages are added 



COIL f) 




COIL C 



0OO2S~/HF 



V 



= rT 



WW 



OoDSMF VSf?Me/i 




8 BAT 
12 To 4-5 'VOLTS 



Figure 2. The wiring diagram of the Simplifigon receiver. This type of set is a very 
desirable one to the bug who is interested in speedy tuning, inasmuch as it has only two 
major controls and two minor ones. The 23 plate condenser and the tickler are about the 
only ones that need adjustment after the set has been adjusted in the filament and 
antenna circuits. Due to the fact that the apparatus is of low loss design and of 
small quantity the receiver will cover Unusual distances. 



with an imposing radio receiver, un- 
consciously eliminating many losses. 

Of late there has been a decided 
tendency toward better design, more 
carefully constructed, simple tuners. 
This movement, originating among ama- 
teur transmitting circles, and heralded 
by their American Radio Relay League 
organ, QST, has caused considerable 
interest among broadcast listeners. In 
recent papers, Mr. K. E. Hassel of the 
Zenith Corporation and Mr. S. Kruse, 
Technical Editor of QST, expound 
several sound rules regarding tuner 
design and construction, and the writer 
feels that these principles are so sound 
and logical that they will no doubt be 
of interest to Radio Age readers. 
General Suggestions 

The writer would like to give a few 
general suggestions on tuner design that 
can be applied to almost any receiver. 
In order to do so, it is necessary to define 
the meaning of a good tuner. 

First of all, with the terrible inter- 
ference we are subjected to, we want a 
tuner that will tune sharply. And we 



in an effort to evade this problem. // 
can't be done! You can't build a perfect 
tuner without resistance of some kind or 
other, but there is at least the consola- 
tion that you can build it with as little 
as possible of resistance. Interference 
grows worse every day, and the ultimate 
thing will be to build a tuner with a low 
resistance, tuned circuit. Just remem- 
ber that. Whether you are building an 
eight tube super-heterodyne or a simple 
first tube circuit, keep the resistance of 
that circuit as low as you possibly can. 
Your reward will come later in the form 
of a sharp tuning, real DX receiver. 
How to Keep Resistance Down 
Permit us to point out just where the 
trouble can be found. First of all we 
can cut down the resistance of our coils 
by winding them with air insulation. A 
good example of this type of air insulated 
coil is the Reinartz coil (the success of 
the Reinartz set will testify to that) or 
else the basket-weave variometer. If 
you must wind the coil on some form, it 
is highly desirable to wind them on a 
common dry cardboard tube. Labora- 



tory measurements actually show that 
dry cardboard tubing has lower losses 
than some of the more expensive mate- 
rials found in commercial receivers. The 
tubing can be carefully dried in an oven, 
and to render it permanently moisture 
proof, it is a good plan to "dope" it with 
a good lacquer or aeroplane dope, such 
as is used on airships. A good mixture 
is acetone, with a quantity of celluloid 
dissolved '"herein. When winding coils, 
the resistance can further be cut down by 
winding them with large sized wires (not 
larger than No. 12 and not smaller than 
20 for use in the tuning circuits) and by 
spacing the wires slightly more than the 
insulation affords. This spacing will cut 
down the distributed capacity, which is 
responsible for the broadened tuningof the 
set. Solid wire should be used in all cases. 

Avoid heavy varnishes and shellacs, 
and bind them into place instead of glue- 
ing them down with some highly resistant 
varnish. Use rosin for soldering, and 
keep the coils fully two inches clear of 
all other units of the receiver. This in- 
cludes panels, rheostats, condensers and 
cabinet. A fan will often wonder why 
his set will work wonderfully outside of 
the cabinet, but the instant it is replaced 
will seem to lose its pep. The cause is 
due to the resistance which is coupled into 
the coil by the presence of a cabinet that 
is too small. 

Connecting resistances into the circuit 
is another defect often found in receivers. 
It is a wise plan to use tube sockets of 
good insulating material, and to avoid 
the use of "moulded mud" camswitches 
or other switching devices. Avoid 
switches in the tuned circuit entirely. 
A porcelain socket is excellent if obtain- 
able. Tapped coils in the tuned circuit 
is always bad business. If it is possible, 
wind the coils to cover the entire wave- 




Figure 3. This illustrates the method 
of winding coils A and B used in the 
Simplifigon circuit. Fourteen steel pegs 
are driven into board in a circle {dimen- 
sions given in accompanying article) and 
the wire is wound around as illustrated 
until the required number of turns have 
been wound. This type of winding and 
mounting is applicable to any circuit mak- 
ing use of coils. You can even wind your 
own honeycombs by this method. 



10 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



length suited, and if this is not possible, 
add an exterior loading coil placed at a 
good distance away from the main tuner. 
When running leads from the high side 
of the coil to the stationary plates of the 
condenser, and from there to the tube, 
run them high up in the air. Don't run 
the wiring of any grid circuit too close to 
the mounting board. 

Condensers 

The most important and probably 
most overlooked factor in making a close 
tuning receiver is the proper condenser. 
The market is certainly flooded with a lot 
of rotten condensers, and a great many 
fans have been duped into buying them 
because of their fancy vernier adjust- 
ments and frills. 

You might have an excellent coil from 
a resistance standpoint, but the entire 
effect is lost when a rotten condenser is 
used. In general, a really good type of 
variable condenser is one of the air in- 
sulated type, with the insulating dielectric 
so placed that it is out of the electro- 
static field as much as possible. The 
leakage paths should be so arranged that 
the current lost will have to travel over 
long paths, which means that the stator 
bolts should be as distant from the rotor 
bearing as possible. This material should 
not be too thick and wide. Where in- 
sulating bushings are used, they should 
be large and spool shaped, so that only 
the rims will touch. The use of thin in- 
sulating washers or bushings of small 
diameter is not good practice. 

The insulation of the condenser should 
be of good hard rubber, pyrex glass or 
other similar insulator of high dielectric 
properties. Composition insulation is 
never to be trusted. Sheet bakelite, 
while not as poor as moulded composi- 
tion or fibre bases is only average in in- 
sulating value as far as a good condenser 
is concerned. 

A metal end plate condenser is very 
good, but care should be exercised in 
purchasing a condenser of this type to 
see that this metal end plate is not con- 
nected to the stationary plates of the 
condenser. The reason for it is this: 
It is always advisable to connect the 
"high" or grid leads to the stationary 
plates of the condenser. If the end plates 
are connected to these stationary plates 
you are going to have trouble in tuning 
due to "body capacity." The rotary 
plates should always be connected to the 
filament circuit when used as a secondary 
control, and when used in either antenna 
or ground, the rotary plates should go 
to the aerial or ground respectively. 

Most condensers use hard rubber end 
plates, however, and the mounting 
screws are fastened thereto. Do not use 
a condenser with a separate vernier con- 
denser, as the losses will be almost as 
high as in the main condenser. A fric- 
tion or geared vernier is the best possible 
vernier that can be used. Choose one 
with a smooth, even adjustment. 

Shielding of the panels or shafts is not 
good practice; it is often worse than 
needless. If a tuner is properly con- 
structed with the stationary plates con- 
nected to the high voltage side (grid) of 
the circuit, no shielding will be necessary. 

Fellows often complain that their sets 
will not work inside of the cabinets, 




SANG TO PRINCE 
Miss Gertrude Lawrence, of Char- 
lot's Revue, the London production 
now playing at the Times Square 
Theater, New York, pictured singing 
to the microphone of radio broadcast 
station WEAF at 65 Broadway. Miss 
Lawrence cabled the prince that she 
was to broadcast and received word 
from him that he would listen in. 

which is only the rule that coils must be 
kept clear manifesting itself. 
Amplifiers 
Two stages of audio frequency am- 
plification should certainly be sufficient 
to bring in the stations of average dis- 
tance on the speaker; and will if the tuner 
is constructed to give a good, clear and 
loud signal to be amplified. The trans- 
formers should have a ratio of about 4:1 
for the first stage and 6:1 for the second. 
Ratios higher than this only serve to 
distort the signals, and really do not offer 
any gain in volume when the signal is 
not clear. 



A Simple Circuit 

Summing up all these requirements 
and limitations on various radio accesso- 
ries, we find that if we observe the above 
rules on any type of tuner the results will 
be pleasant. 

The ear is a very poor judge in the mat- 
ter; it is too sluggish to compare or notice 
small differences made in eliminating 
losses. If we took a tuner and eliminated 
three per cent of the losses, we would 
not notice any appreciable change in 
signal strength, but suppose we made 10 
such changes, eliminating nearly thirty 
per cent of the losses, it would certainly 
make you sit up and wonder why you 
didn't do that before. 

Now if we make a tuner incorporating 
the above requirements, we will have a 
tuner that incorporates close tuning prop- 
erties, substantial range, and reliability. 
It is entirely possible to make a tuner 
that includes the remainder of the defi- 
nitions. 

We don't want to couple the set di- 
rectly to the antenna, as in the case of 
the ancient single circuit receiver, be- 
cause even if we make a wonderfully ef- 
ficient tuning circuit, we spoil it all by 
coupling a highly resistant broad tuning 
part of the receiving system to the set. 
This explains the broadened tuning of 
the single circuit receivers. However, 
we can couple it loosely, and let the an- 
tenna act aperiodically as a collector only, 
and not as a part of the tuning circuit. 
If we do this, we also reduce the nuisance 
of reradiating receivers, as a circuit of 
this type is not so strong an oscillator. 

The Simplifigon 

With the requirements above men- 
tioned in mind, we will proceed to build 
a tuner that will incorporate all these 
desirable qualities. The circuit shown 
in Figure 2, after a close glance, appears 
to be a "conglomeration," as Jack Nelson 
would say, of the single circuit receiver, the 
Reinartz, Haynes and a few others. 
We can't call it either or any of them, so 
for purposes of easier reference we will 
call it the "Simplifigon." Simplifi for 
the simpleness of it and the gon for old 
times' sake. 

The circuit is the suggestion of Mr. 
K. E. Hassel, and the mounting is a com- 
pound idea of Mr. Perry O. Briggs, 
Rado 1BGF, and the writer. 

Construction 

Before we construct, of course, we will 
need our parts, which are as follows: 

1 7x14 Bakelite or Formica Panel. 
1 23 plate, .0005 vernier condenser with 
gear or friction vernier. 

1 Rheostat to suit tube used, vernier 
type. 

1 Tube socket. 

1 Grid condenser .00025 MFD. 

1 Phone condenser .001 MFD. 

1 Grid leak tubular type, interchange- 
able. 

70 feet of No. 16 DCC wire solid 
copper. 

16 feet of No. 18 Annunciator (bell) 
wire. 

Two feet flexible lamp cord. 

Waxed string, mounting board, bind- 
ing posts, bus bar, and two hardwood 
(Continued on page 17) 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



11 



Junior Heterodyne Transformers 

By JOHN B. RATHBUN 



SHORTLY after the January number 
of RADIO AGE was issued, the 
office was in receipt of many letters 
and telephone calls requesting infor- 
mation on the subject of the long wave 
radio frequency transformers necessary 
for the Junior Super-Heterodyne. Such 
transformers were at that time difficult 
to locate, and owing to the Radio 
Corporation taking the UV-1716 off 
the market, the heterodyne constructors 
were at a loss as how to proceed. In 
many cases, we advised the use of the 
UV-1714on a wave length of 3, 000 meters, 
necessary changes being made in the two 
coupling coils to accommodate the lower 
wave length. This, however, was not 
entirely satisfactory as there was a pro- 
nounced "feedback effect" through the 
plate-grid capacity on this wave length, 
and a greater tendency toward self- 
oscillation in the tubes. The recommend- 
ation was simply made so that the 



the wave length band and introduces 
other difficulties as well. 

So far as the hookup itself is con- 
cerned, it makes no difference whether 
the system operates at 3,000, 5,000 or 
10,000 meters except that the size of 
certain units are changed. The connec- 
tions are just the same in all cases, the 
difference lying in the number of turns of 
wire on the coils and the capacity of 
the condensers. As to the relative per- 
formance on different wave lengths, there 
is a great diversity of opinion at the 
present time but I note with satisfac- 
tion that there is a decided tendency 
toward wave lengths as great as 10,000 
meters. At such high wave lengths there 
is little tendency toward capacity coup- 
ling between the various radio stages, 
less interstage coupling within the trans- 
former itself, and less trouble with tubes 
that are mysteriously inactive. At 3,000 
meters, the frequency is still high enough 



Whether the higher ratios are justified 
is still a matter of experiment, but it 
may be said that a ratio of unity (1 to 1) 
is quite satisfactory, and the ratio per- 
mits of smaller units and coarser wire 
in both the primary and secondary 
coils. This gain due to the reduction in 
electrical resistance somewhat offsets 
the gain due to the high ratios. There 
has been much discussion on the subject 
of the proper ratio, and this is not yet 
settled so far as the average builder is 
concerned. 

From various experiments performed 
in Chicago, it would seem that impedance 
coupling has many desirable qualities, 
not alone from the standpoint of cost but 
from the performance as well. In this 
form of coupling a single inductance coil 
is used, usually a honeycomb, with a 
fixed condenser connected across the 
outer ends of the coil. This is small and 
compact and it certainly functions well. 




enthusiastic builders could get on the 
job at the earliest possible moment. 

It will probably be good news to the 
majority of readers to know that the 
transformer situation is clearing up and 
that in a short time that there will be a 
number of heterodyne transformers 
placed on the market. Both iron core and 
air core types are represented by these 
makers, and a wave length range from 
3,000 to 25,000 meters is offered. 

One great trouble with the commercial 
transformers of the present time is that 
the old radio frequency practice of a 
wide wave length band is followed, and 
this is not the proper characteristic of 
a heterodyne transformer. For example, 
a wave length range of from 5,000 to 
25,000 meters in a single transformer 
lowers the possible amplification. Ac- 
cording to heterodyne theory, such 
transformers should be rather sharply 
tuned so that a fairly narrow peak of 
amplification is shown. This is, of 
course, best attained by the use of air 
core type transformers since the intro- 
duction of a metal core tends to broaden 



to cause appreciable capacity effects 
between the grid and plate of the tubes. 

It is interesting to note that 10,000 
meters corresponds to a frequency of 
30,000 cycles per second, and that this 
frequency is only a little above audio 
frequency. For this reason, iron core 
transformers are more effective at 10,000 
meters than at longer wave lengths since 
a deeper magnetic penetration is had in 
the core iron without extreme subdivision 
of the iron. Give us a long enough wave 
length and we can employ audio fre- 
quency transformers in place of radio 
frequency types, and on frequencies 
approximating 15,000 cycles per second 
the use of audio transformers is entirely 
feasible. It has often been the desire 
of the writer to experiment with the 
very low frequencies, just above audi- 
bility, using standard types of audio 
frequency transformers for the purpose. 

Transformer ratios of the long wave 
transformers is a variable quantity among 
commercial types, ranging from a ratio 
of 1 to 1, to 4 to 1 or even higher. 



The size of the coil and the condenser 
depends upon the frequency determined 
upon and is easily and cheaply built 
by any constructor. The "tuned im- 
pedance" is connected to the plate 
circuit of each stage of radio frequency, 
one coil per tube, with the remaining 
end connected to the positive "B" 
battery connection (*B). A small 
condenser is connected in the line run- 
ning between the plate and grid of ad- 
jacent tubes to prevent the "B" battery 
current from paralyzing the grids. 

In the following table is given the size 
of honeycomb coil and the size of the 
shunted fixed condenser required for the 
various wave lengths. 

Size of Size of Wavelength 

Honeycomb the Fixed in 

in Turns Condenser Meters 

200 0.001 2,870 

250 0.0005 2,800 

250 0.001 _ 3,910 

300 0.0005 _ 3,490 

300 0.001 „„ 4,900 

400 0.0005 4,400 



12 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 




500._ 0.0005 5,750 

500 0.001 8,070 

600 0.001 .____ 11,600 

To insure proper operation, all of the 
units should be carefully adjusted so 
that the impedances are as nearly equal 
in each stage as it is possible to make 
them. Testing each unit with a wave- 
meter is the surest method. 

Honeycomb Coil Transformers 

Very frequently the transformers can 
be easily built at home and good results 
can be obtained if the work is carefully 
conducted. The cost is very much lower, 
and this is a great factor when three or 
more stages of radio frequency amplifica- 
tion are used. Of these homemade de- 
vices, the honeycomb coil transformer 
is the most easily built since suitable 
honeycomb coils can be easily obtained 
on the market and can be quickly 
assembled. Very good results can be had. 

Figure 1 shows how the two coils 
constituting the primary and secondary 
are placed side by side and mounted on a 
cardboard mailing tube. About one- 
eighth inch separation is allowed between 
the coils, but this is not a critical value. 
A fixed condenser (K is connected 
across the ends of the primary coil only 
to increase the natural wave length of 
the coil and to reduce its size. The 
number of turns in the primary and the 
corresponding size of the condenser K) 
for a given wave length can be determined 
from the table of impedances just given. 
In this case, where both coils are of the 
same size, the transformer ratio is of 
course 1 to 1, but if a higher ratio is de- 
sired the number of turns in the secondary 
can be increased but the size of the 
primary remains unchanged as this 
depends upon the wave length. 

The terminals of the coil are marked 
as usual for the grid (G), the plate (P), 
the negative "A" (-A), and the ( + B) 
battery connections. The grid connec- 
tion (G) should be taken from the out- 
side turn of the secondary winding. 
The wire should be No. 28 D. S. C. as is 
usual with the commercial coils of this 
size, but No. 30 gage can be used where 
the coil is to be reduced to its smallest 
possible dimensions. The paper tube, 
(T) is the only core, no iron being used. 
In assembling this transformer care 
should be taken that the direction of the 
turns is the same in both coils. 

When a two to one ratio is required, 
we can either have a secondary coil with 



twice the^number of turns, or else employ 
one primary coil with two equal second- 
aries mounted on either side of the 
primary, the two secondary coils being 
connected in series. This construction 
is shown by Fig. 2 where the primary 
coil (PRI) is sandwiched in between the 
two secondary coils (SEC). The second- 
aries are connected in series by the 
bridge wire (M) and particular care 
must be taken so that the windings of the 
coils are in the same direction. If this 
is not done, then the coils will "buck" 
one another and no transformation will 
take place. The fixed condenser (K) 
is connected across the primary coil as 
usual, and the size of this coil and the 
condenser are determined by the wave 
length table as before. This is a very 
bulky and rather expensive construction. 

A more compact winding, particularly 
adapted to wave lengths above 5,000 
meters where many turns are required, 
is the "spool type" transformer of 
Figure 3. This spool contains three 
grooves, the center groove containing the 
primary winding while the two outer 
grooves contain the two halves of the 
secondary winding. The secondaries are 
connected in series as in Figure 2, and 
needless to say, all coils are wound in 
the same direction. No tuning con- 
denser is used for the primary coil as the 
natural wave length of this coil alone is 
sufficient to bring the wave length up to 
10,000 meters without the aid of the con- 
denser. As each half of the secondary 
contains twice as many turns as the 
primary, it is evident that the total 
transformer ratio is four to one. 

The primary winding in the center 
groove consists of 500 turns of No. 30 
D. S. C. wire. Each of the secondary 
coils in the two outer grooves consists of 
1,000 turns of No. 36 D. S. C. wire making 
a total of 2,000 turns in the primary and 
giving a total transformer ratio of four 
to one. 

After these coils are wound, and the 
outer ends are fixed by a dab of sealing 
wax we can place them within a metal 
container or else place them within a 
metal tube for protection and shielding. 
The four ends of the coil are then brought 
out to the binding posts after the two 
secondary coils have been connected in 
series as shown by Figure 2. To connect 
the coils of the secondary in series, the 
inside end of one of the outer coils is 
connected to the outer end of the other 
outside coil. Care should be taken to 



mark the outside end of the secondary 
by (G), thus indicating that this end goes 
to the grid of the following tube. This 
is important as the capacity effect is 
much less when connected in this way 
than when the inner end is connected to 
the grid. 

One end of the central primary coil 
( + B) goes to the positive "B" battery 
while the other end (P) goes to the plate 
of the preceding tube. It is likely that 
the best results are obtained if the outer 
end of the primary is connected to the 
plate. 

Of course this compact construction or 
spool wound transformer can be made 
for other wave lengths, but owing to the 
comparatively great amount of dis- 
tributed capacity in a winding of this 
sort, it is not so effective on the shorter 
wave lengths as the honeycomb type of 
coil. It should be remembered that the 
capacity effect increases rapidly with a 
decrease in wave length or increase in 
frequency, and what might prove per- 
fectly correct at 10,000 meters will not 
be efficient at 3,000 meters. When a 
number of turns are wound over each 
other in layers as in the last type of 
transformer, each turn acts as a plate 
of a condenser in regard to an adjacent 
turn, and this capacity between turns 
becomes an appreciable effect on wave 
lengths below 10,000 meters. Winding 
the turns in zigzag fashion as in honey- 
comb coils greatly reduces the capacity 
of the winding a's succeeding turns are 
not parallel but cross each other at 
nearly right angles. 

To insure proper insulation, the trans- 
formers should be carefully dried out in a 
moderately warm (not hot) oven until 
all moisture is expelled from the wire 
covering. They can now be slipped into 
their casings and seal up moisture tight. 
A metal casing such as a brass tube is 
desirable since it greatly reduces the stray 
field set up by the transformers and thus 
prevents inductive disturbances in the 
circuit. As an additional insurance 
against this "coupling" by the external 
field, adjacent transformers should be 
turned at right angles to each other, and 
separated by as great a distance as pos- 
sible with the space allowed. It is well to 
follow neutrodyne practice in regard to 
the spacing of the tubes and transformers 
in the receiving set, keeping the tubes and 
transformers well apart to prevent 
coupling between the radio frequency 
stages. 



RADIO AGE— "THE MAGAZINE OP THE HOUR' 



13 



A Tuned Radio Frequency Amplifier 

Will Increase Signal Volume, Selectivity and Receiving Range of Any Standard 

Receiver 

By J. A. GALLANAN 



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WHILE the most simple type of 
amplification is that of audio 
frequency, so named because it 
is handling currents of frequencies within 
the audible range, there is another type 
known as radio frequency amplification 
and which is at the present time the sub- 
ject of much discussion and speculation 
and which is coming more and more into 
requirement for long range reception as 
well as in connection with short antenna 
systems and loop aerials. 

In audio frequency, amplification is 
accomplished after the signal has passed 
the detector, while in radio frequency 
amplification the original signal wave is 
amplified before it is passed to the de- 
tector or rectifier. An advantage of this 
method lies in the fact that it amplifies 
the wave only and not the many, little 
irregularities and imperfections which 
exist in the receiver and audio frequency 
amplification equipment. Furthermore, 
most detectors have a critical point at 
which they begin operating. Signals 
that come in weaker than this critical 
point of the detector make no impression 
upon it and are entirely lost. Thus it is 
evident that any signal which has failed 



to actuate the detector will not be heard. 
With radio frequency amplification, on 
the other hand, there is virtually no 
critical point and even the weakest signals 
can be built up to the desired degree be- 
fore being passed on to the detector to be 
rectified to audibility, and from there 
on for further volume through stages of 
audio frequency. 

Radio frequency is by no means a 
simple matter and is only now emerging 
into popularity in this country. The 
subject cannot be completely covered 
in an article of this nature even though 
the author were in a position to essay 
the task. 

Radio Frequency History 

It may be interesting to include a bit 
of history concerned with the subject. 
This system of amplification dates back 
a little over ten years, a relatively long 
time in development of radio communica- 
tion. At that period two Germans were 
diligently trying to solve the problem of 
more sensitive reception, and amplifi- 
cation of the radio signal before detec- 
tion seemed to be the answer. So we see 
that it is not a new development, but 
rather one of the oldest. It made its 



advent at about the same time as the 
famous Armstrong regenerative circuit. 
It did not have the distinction of being 
born in America, but in Germany. 

It came into its own almost immediate- 
ly in Europe and during the late war there 
was practically none other in use for 
sensitive receivers. Its rather belated 
introduction to the fans of this country 
is heralded by many as the dawn of a 
new day. 

The writer has experimented with 
radio frequency in its various forms of 
untuned and tuned with differing degrees 
of success. 

It is admitted that the ordinary radio 
frequency transformer responds over a 
certain limit of wave lengths with a loss 
of volume on either side of such wave 
band. No matter what method is used 
to broaden the wave band with a trans- 
former of fixed ratio there is still one 
band that is favored while efficiency 
drops off at either side making trans- 
former coupling a serious problem. 

Inductive coupling between the an- 
tenna and grid circuits is accomplished 
with a standard variocoupler and does 
not noticeably increase the selectivity. 
(Continued on page 18) 



14 



RADIO AGE— "THE MAGAZINE OP THE HOUR" 




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RADIO AGE— "THE MAGAZINE OF THE HOUR" 



15 



How to Make the Kopprasch Receiver 



By FELIX ANDERSON 

Technical Assistant, Radio Age 



EVER since the original presentation 
of the Kopprasch circuit in the 
April, 1923, issue of RADIO AGE, 
there has been a rapidly increasing 
interest in that circuit for two major 
reasons. Primarily, because the Kop- 
prasch i-ircuit offers unlimited possibili- 
lies with respect to long distance recep- 
tion, and seccnJarily, due to its ability 
to reach out and get the long distances 
even in dead spots without fading. 
Clarity of reception and freedom from 
tube noises is another one of its impor- 
tant assets, and due to the fact that it has 
figured prominently in the Pickups and 
Hookups section of this magazine, we are 
presenting it to our newer readers who 
have evinced a tremendous interest in it. 

This set was designed by Mr. A. H. 
Kopprasch of Chicago, who spent many 
months in perfecting this novel and un- 
usual circuit. 

The strength of signals obtained when 
using this circuit is much greater than 
any average circuit, and it is even more 
pronounced when standard storage bat- 
tery tubes are used. The music, once the 
set is adjusted, comes in very clearly 
and distinctively, and stations in Califor- 
nia and Oregon have been clearly and 
distinctively heard in Chicago with but 
a single tube. These stations were not 
only heard but were held as long as de- 
sired without the customary fading away 
which is so common with reception at 
such great distances. 

The outstanding feature of the set is 
the peculiar arrangement of the vari- 
ometers, one of which is connected in par- 
allel and the other in series. The antenna 
inductance is wound on a paper tube, 
which is placed between the two vari- 
ometers and in inductive relation to them. 

Figure 1 shows how this mounting is 
accomplished, as does the accompanying 
sketch. 



GRID LEAK 




Z3PLATE VARIABLE 
VERNIER CONDENSER 



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8- BATTERY 
Z2'/2.VOLT?: 



GROUND 



Figure 2 — The wiring diagram of the Kopprasch receiver, 
connections of the variometers. 



Note the unusual 



board tube, two inches long, and of 
sufficient diameter to allow the rotors 
of the variometers to clear it. Fifty- 
five turns of No. 20 DCC wire is wound 
on the tube, tapping at every eleventh 
turn. These taps are connected to the 
switch points as shown in Figure 2. 

This coil should be wound in the 
opposite direction to the stators of the 
variometers. The starting end of the 
winding of the antenna inductance is 
connected to the series variometer with 
the antenna post connected to the junc- 
tion between them. 

The variometer on the left is connected 



The tube is made of any heavy card- 

MOUNTING OF VARIOMETERS AND TUBE 

VARIOMETER^ VARIOMETER^ 





/ 

. / 
1 




\ 

\ 


TUBE 


/ 

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/ 




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Hfture 1 



in parallel, that is, one end of the rotor 
winding is connected to one end of the 
stator winding as shown under "parallel" 
in Figure 3. The connections are made 
at the points indicated at C. A 23 plate 
vernier variable condenser is connected 
across the terminals C and C as indicated 
in Figure 2, on the wiring diagram. 

The remaining apparatus is standard, 
the grid leak being of the ordinary 
tubular interchangeable type, and the 
grid condenser of the conventional 
.00025 MFD capacity fixed type. The 
battery used will be determined by the 
type of tube used, as will the rheostat. 
A B battery of the tapped variety is pre- 
ferred, as often tubes will function more 
effectively when about 16 or 18 volts is 
used to energize the plate. Phones should 
have a resistance of about 3000 ohms. 

In mounting the variometers, it is a 
good plan to mount them firmly on the 
mounting board in such a way as to 
be able to force the inductance tube 
between them firmly. If the tubing 
slides down, it may be fastened with 
sealing wax. 

Most all of the causes for trouble in 
this set are found in one of two places: 
either in the winding on the tube in the 
incorrect direction with respect to the 
direction of the stator coils on the 
variometers or else the value of the grid 
leak is not correct. 

By carefully examining the stators, 
it is easy to find the direction of the wind- 



16 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



fr-SimOR COILS 



6- RDTDR COfLS 



C CONHFCTION PDl/^S 





PARAIL& 



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Figure 3. The above drawings illustrate the method of making series and parallel connections of the variometers used in the Kop- 
prasch circuit. The rotors are shown as being outside, to illustrate the connections. 



ing; when the two variometers are placed 
side by side the stators should appear to 
be a continuation of the winding in the 
same direction. 

The other case of trouble which may 
be present is a beat noise in the phones. 
This may sound like a hum or a series of 
slow knocks, and often presents itself 
in the form of a screech. This is remedied 
by inserting a grid leak of lower resistance 
in the clips Careful adjustment of this 
leak is necessary to obtain the best 
results, and several values should be 
tried out until the best one is found. 

Without doubt there are f ans who 
desire to add two stages of amplifica- 
tion, which is added in the manner 
exemplified in Figure 4. 



Large Antennas 

Hartford, Conn. — It is seldom that 
an amateur radio long distance test is 
accomplished without there being un- 
covered some technical truth destined 
to have a far-reaching effect on amateur 
transmission and frequently radio com- 
munication in general. Recently ama- 
teurs in France and Connecticut suc- 
ceeded in carrying on the first short wave 
communication between the two conti- 
nents. After thoroughly going over the 
construction of French 8AB and Ameri- 
can 1MO, the two stations most promi- 
nent during the tests, S. Kruse, technical 
editor of QST has been able to draw- 
some interesting conclusions. 

Mr. Kruse believes the transatlantic 
success was due primarily to the fact 



that each station participating used 
antennas that are large for the waves 
they are working. "Working an an- 
tenna that way," he says, "gives high 
radiation efficiency. The moment that 
statement is made the tribe of ampere- 
hounds will rise in protest. Nevertheless 
we are putting more power into the ether 
than ever before, though the antenna 
current does drop. 

"The idea has now been put through 
some weeks of steady work with ama- 
teurs and in every case the successful 
American stations have been using big 
antennas with series condensers. Most 
of us do not have 'X' licenses, so we can- 
not work on 100 meters, but the lesson 
is just as good at 150 meters. Be sure 
to give your antenna a fundamental 
wave lencrth of at least 220 meters." 



AERIAL 

W 



VARIOMETER 




ANTENNA* 
INDUCTANCE 




GRID LEAK 
AND CONDENSE^. 



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VARIOMETER. 



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23 PLAT _ 
VERNIER 
CONDEN3ER. 



.GROUND 






A BAT 



■ffibL^lSS-ro 1 AMPLIFYING 

TRANSFORMER-!. TRANSFORMER^- 




40-60 V 



WM'l#Hi 



Figure 4. The Kopprasch circuit in connection with two stages of audio frequency amplification. A receiver of this type will bring 
in distant stations with considerable volume on the loudspeaker. Amplifying transformer No. 1 should have a ratio of about 3 1-2 or 
4 to 1 while the second should have a ratio of not greater than 6:1 . 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



17 



The Simplifigon 
Receiver 

(Continued from page 10) 

sticks boiled in paraffine. Batteries, 
cabinet and phones. 

1 piece of Bakelite or Formica, 6x4 
inches. 

After you have assembled this list of 
apparatus, lay the panel out according 
to the sketch shown in Figure 1. The 
tuner shows how simple the general lay- 
out of the set is. If you wish, suit your 
own individual taste in the matter, so 
long as the foregoing requirements are 
kept in mind. 

Winding the Coils 

The only hard part of the entire set is 
the winding of the coils. This however, 
requires no skill, but a goodly exhibit of 
patience. 

Starting with coil A, procure a card- 
board tubing or other form which has a 
diameter of 3 inches. Around this form, 
wind 10 turns of the No. 16 DCC wire 
and allow a few inches at each end for 
connections. Slip the coil off the form, 
and bind the wires together firmly with 
a piece of waxed string as shown at A 



in Figure 1. With another piece of 
waxed string, fasten this coil to the wood- 
en shaft or stick which has been boiled 
in paraffine, as also shown. This com- 
pletes coil A. 

To wind coils B and C is a little harder. 
Procure 14 steel pegs (finishing nails 
without heads will do) and set them in a 

4 inch circle as shown in Figure 3. Start- 
ing at peg No. 1, with the remaining 
No. 16 DCC wind around peg No. 4, 
skipping 2 and 3, from 4 to 7 inside of 

5 and 6 and so on as shown. Coil B 
should have from 45 to 50 turns. This 
number will vary, due to the fact that 
hand wound coils cannot be made uni- 
form. In all probability some of the 
No. 16 wire will be left over, and this can 
be slipped into spaghetti tubing for wir- 
ing. The coil is bound up in the same 
manner as was coil A, with the wax 
thread, and is supported by winding the 
wax thread firmly around a heavy piece 
of cardboard and mounting the entire 
coil and cardboard on two small blocks 
as shown at B, Figure 1. 

Coil C is wound in the same manner 
as coil B, with the exception that the 
circle in which the pegs are set is only 
2 7-8 inches in diameter. The winding is 
done in the same manner, and should 
be of from 18 to 22 turns. It is best to 
wind it with about 22 turns and decrease 
this number until the right value of 



tickler for the particular tube you are 
using is found. This coil is also fastened 
to one of the sticks. 

These sticks are screwed to knobs or 
dials, and are used to vary the coupling 
of the coils. 

Connections to the two movable coils 
are made with the flexible lamp cord, 
permitting the coils to be rotated. Wire 
the set according to the diagram shown 
in Figure 2, or, if you choose, Figure 1. 

Connect the antenna, phones and bat- 
teries to the posts indicated and set 
the filament, rheostat and tickler so that 
the tube oscillates gently. Rotate the 
secondary tuning condenser until a sig- 
nal carrier wave is heard, and clear up 
the signal with the tickler and rheostat. 

While this is only one of the many 
efficient circuits that can be constructed 
upon these principles, it is entirely em- 
blematic of the ideals of low loss, princi- 
ples set forth in the foregoing paragraphs 
and with two stages of audio frequency 
amplification built into a separate cabi- 
net as described in the August, 1923, 
issue or the RADIO AGE ANNUAL, this 
set should prove equal to any three-tube 
set devised. The writer does not advise the 
use of radio frequency with the Simpli- 
figon, feeling that if you desire anything 
better than a good regenerative circuit 
with two stages of audio frequency am- 
plification build a Super-heterodyne. 




IN WONDERLAND 
Little Miss Noreen Alley, a Chicago fan, will tell you all about the six-tube receiver made by her daddy, Norman 
Alley, of the International Newsreel, as soon as she has given it a thorough tryout. She is shown trying to pick up 
KGO on the loud speaker. 



18 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



— — ■atinmfliD>-f 



"""-amnntto— . 




A Tuned Radio Fre- 
quency Amplifier 

(Continued from page 18) 

and somewhat decreases sensitivity be- 
cause of the losses always entailed in 
inductive coupling. 

It is important, then, to the experi- 
menter what method of radio frequency 
amplification is employed. In the expe- 
rience of the writer straight tuned radio 
frequency is considered the most stable 
and easily adapted to practically any 
standard circuit. 

A single stage of radio frequency am- 
plification in the manner of our schematic 
diagrams is in the nature of a wave trap 
designed to amplify the frequency to 
which it is tuned. 

The following circuits were developed 
as affording the best results on all receiv- 
ers of experiment conducted. 

While we are showing two amplifier 
circuits it will be seen that they differ 
only in that one uses a variable capacity 
(condenser) and the other a variable 
inductance (variometer) to tune the plate 
circuit. Results were favorably compara- 
ble in either method.' 

Apparatus 

In both circuits the same type of an- 
tenna tuning unit is employed. In No. 1 
the plate circuit is tuned with a standard 
variometer. The connections as shown 
provide for the use of common A and B 
batteries for receiver and radio frequency 
amplifier. No negative B connection is 
indicated as it is made through the A 
battery wiring in the receiver. 

Both coils shown in No. 2 are fifty- 
turn honeycomb coils. These can be 



substituted by their equivalent which is 
accomplished in two coils wound each 
with forty turns of No. 22 DCC wire on 
three-inch cardboard tubes. Both con- 
densers are twenty-three plate variables, 
not necessarily vernier. While No. 2 
shows use of a separate B battery it is 
understood that either method can be 
used, being optional in either circuit. 
Results afforded are of equal satisfaction. 

A by-pass condenser, .002MF is con- 
nected in parallel with the B battery, to 
prevent radio frequency losses in it. 

A U V-201 tube was demonstrably the 
best radio frequency amplifier tried. 
A 400 ohm potentiometer is effective for 
either a six volt or a peanut tube. The 
value of rheostat is determined by the 
tube used. The condenser to be con- 
nected between the output of the radio 
frequency amplifier and the antenna 
binding post of the receiver circuit is a 
.00025MF (Dubilier preferred). (Be 
careful to have no grid leak on condenser). 

Binding Post Connections, in either 
circuit, No. 1 to antenna binding post 
of receiver. No. 2 to positive A. No. 3 
to negative A. No. 4 to positive B. 

How to Tune 

A good operator will never use an 
oscillating detector to receive radio 
phone broadcast. . . . The oscillat- 
ing detector interferes not only with 
neighboring receivers but will not give 
stability and good quality of reception. 

Oscillations are presented by turning 
the potentiometer "stabilizer" arm to- 
ward the positive side. A radio frequency 
amplifier tends to oscillate as the grids are 
placed negative, and amplification is at 
maximum at a point just below where 
oscillation starts. 

The following pointers may be useful. 



The writer has observed many times that 
operators in using a one-step tuned 
radio frequency set will turn the radio 
frequency tube to full brilliancy and then 
go ahead and turn up the impedance 
variometer or condenser until oscillation 
starts, imagining that he is then operating 
at full efficiency and in proper fashion. 
This is, however, not the case. Most 
tubes will start oscillating some time 
before the correct impedance value is 
reached. 

The way to realize as much as possible 
from a tuned radio frequency amplifier is 
to keep oscillation down until the correct 
impedance value is reached. This is 
found as described herein; it will be ob- 
served that as the radio frequency tube 
is turned down, the band through which 
oscillation occurs as the impedance is 
varied narrows down very rapidly. 
By carefully lowering the filament tem- 
perature we eventually find a point where 
the tube will oscillate through but one or 
two degrees of scale on the dial That 
point represents the value for which we 
aim. If you simply turn your tube all 
the way up, and then go ahead and tune 
your impedance until oscillation starts, 
you might as well junk your outfit as 
you are not realizing the possible gain of 
efficient operation. To get that gain you 
must resort to a possibly tedious method 
of keeping the tube low until you find 
the impedance value for the particular 
wave you are working up, and this 
means taking time. 

A word about construction is in order. 
When building this radio frequency 
amplifier patience and skill are rewarded. 
Wiring must be neat and all joints secure. 
The individual units and the circuit 
should be tested individually before try- 
ing the receiver as a whole, 



RADIO AGE— "THE MAGAZINE OP THE HOUR' 



13 



Adding Radio Frequency to the Vari- 
ometer Set 



By BRAINARD FOOTE 



T! 



| HE OLD two variometer and vario- 
coupler regenerator was a good 
set in its day but the advent of 
newer circuit arrangements puts it out 
of date today. The owner of the standard 
regenerative outfit, however, doesn't 
want to throw away or junk most of his 
receiver just to get a better receiving 
range, because of the expense involved. 
And yet, nothing has been offered to him 
in the way of improvement which doesn't 
mean just that. 

However, there's nothing the matter 
with the variometer, and it may be 
utilized very effectively in a radio fre- 
quency circuit which implies no addi- 
tional equipment other than another 
tube, socket and' rheostat. The vario- 
coupler is made into a radio frequency 
transformer, and the left-hand vari- 
ometer in the set becomes the secondary. 
The aperiodic antenna system is adopted, 
and the tuning range of the first variom- 
eter is boosted by means of a small shunt 
condenser. 

What is Gained 

The advantages of the change are 
several, foremost among them being, of 
course, a considerable increase in DX 
reception. Selectivity also is improved, 
and the operating controls are reduced 
to two only, although there may appear 
to be more than that in the drawings. 
Besides the regular equipment of the 
standard variometer set, the following 
parts are needed: 

UV-201-A tube. 

Tube socket. 

Rheostat. 



Mica «5h«e1s 



Copper PjQt6sBOy awWE 






>olt^ 



Completed 



Cl»ps 





Figure 1 — Close-up of the parts used in making the shunt condenser 
for boosting the tuning range of the variometer. Paraffined paper may be 
used with as good results as obtained with mica sheets. 



Piece of copper or aluminum sheet, 
2 by 1 inch. 

Piece of mica or heavy paraffined 
paper, 2 by 4 inches. 

Ten or twelve feet of bell wire. 

Figure 1 illustrates how the parts for 
the little shunt condenser are cut and 
put together. This is condenser "C" 
on the circuit diagram, and it is needed 
to raise the wave length range of the 
variometer, which now is to function 
as the secondary all by itself. If one 
hasn't facilities for drilling the copper 
plates, which are cut to a diameter of 



HxvJP- 




Figure 2 — View of the antenna coupling coil in place alongside the 
variometer. Bell wire, seven turns, form the coil, and it is held in position 
with the aid of some strips of tape and two little tacks. 



one inch, the hole in the center may be 
roughly punched out with a small chisel. 
The actual capacity of the condenser 
is not of particular importance, since 
the thickness of the paper or mica be- 
tween the two plates may be altered by 
the use of more or less sheets until the 
correct capacity is determined. This 
may best be done by experiment. The 
connecting clips for the condenser are 
cut off from an old "B" battery and sol- 
dered to the projecting lugs of the con- 
denser plates. The hole in the plates 
must be large enough so that the 6-32 
holding screw cannot touch them as it 
passes through. 

The Coupling Coil 

Figure 2 illustrates the method of 
mounting the antenna coil. It is impor- 
tant to determine which side of the vari- 
ometer is to be connected to the grid, and 
then to mount the coupling coil at the 
OTHER end, so that it will be at the 
"low potential" end of the variometer. 
This insures high voltage applied to the 
grid. Moreover, if the variometers arc 
of a type that use the front shaft as a 
connection, this must be the filament 
end, or there will be some hand capacit\ 
effect. The coupling coil is made of 
eight turns of the bell wire, wound first 
on a tubing or other cylinder about four 
inches in diameter and affixed by a couple 
of tacks to the side of the variometer. 
Two strips of tape hold the coil in shape 

The remainder of the connections 
aren't complicated. The primary of the 
variocoupler now becomes the primary 
of the radio frequency transformer, and 
the plate terminal of the R. F. amplifier 
socket is joined to one of the switch arms. 
The other switch lever is wired to the 
plus "B" battery. Thus the number of 
turns in the primary may be varied at 
will. The grid circuit of the detector is 



20 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



left intact, but it is essential that there 
be a .001 by-pass condenser connected 
from the detector plate terminal to one 
side of the filament. The UV-201-A 
tube is recommended as a superior de- 
tector for this type of receiver, although 
the UV-200 is almost as satisfactory. 

The ground is connected to the nega- 
tive side of the "A" battery, as is the 
"grid return" lead of the radio frequency 
tube. The "B" battery should be at 
least 67 1-2 and preferably 90 volts. Of 
course, if the UV-200 is used as the de- 
tector, the detector plate circuit should 
be tapped in at the 22 1-2 volt point in- 
stead of the 90 volt point, as illustrated 
in Figure 3. 

How to Operate It 

First of all, set the switches to include 
at least half of the variocoupler's pri- 
mary winding, and set the rotor at the 
position of maximum coupling, where it 
may be left, and need not be touched 
again. Then set the left-hand vari- 
ometer at about half its scale reading and 
turn the other one until you hear the 
customary "rushing" noise of regenera- 
tion. Reduce the number of turns in 
use on the variocoupler until regenera- 
tion is heard only over a very few (5 or 
6) degrees of the variometer scale. Then 
swing both variometers up and down 
their scales, keeping them in tune so that 
regeneration is taking place, until the 
carrier wave of a broadcasting station 
is heard. This is evidenced by the usual 
"whistle." 

Now still further reduce the number 
of turns on the coupler until oscillation 
stops. Then retune the variometers un- 
til the station is heard clearly without 
any oscillation. When this position is 
found, it will usually be possible to tune 
up and down the scale without starting 
oscillations at all, but with adjustments 
set so that the point of oscillation is very 
close. Thus the set cannot radiate and 
annoy other listeners, and at the same 
time, the volume of the DX stations will 
be very much increased, doubled and 
tripled in many cases. The selectivity 
will be found surprisingly sharp, so that 
it is necessary to tune slowly for fear of 
passing over a station's wave without 
noticing it at all. 



Should the high wave broadcast sta- 
tions come in with the left hand vario- 
meter set at less than two-thirds scale, 
the shunt condenser has too large a ca- 
pacity. This may be remedied by un- 
screwing it and inserting another sheet 
of insulation to double the distance be- 
tween the plates. Another sheet may 
be added should that also fail to "spread 
out" the tuning on that variometer suf- 
ficiently. 

The variocoupler makes a very con- 
venient radio frequency transformer 
when used in this manner, and the tens 
and units taps are ideal for close regula- 
tion of the coupling. The more turns in 
use on the primary, the greater will be 
the feed-back to the grid circuit of the 
first tube, and sufficient turns should be 
cut into circuit to bring the set up to the 
position of maximum sensitivity just 
before oscillation begins. The actual 
tuning controls resolve themselves into 
two, since the coupler controls never 
need be touched unless perhaps to "put 
a damper" on some extra loud local sta- 
tion, or to "pep up" the volume from a 
very faint fellow. The clearness ob- 
tained with this arrangement is pleasing 
indeed, and the volume also is quite a 
bit greater. The increase in receiving 
radius is the addition which will be of 
most value, and the ease of tuning and 
absence of hand capacity will make the 
set a joy to use. 

Next month: How to reflex the set. 



No S O S From NERK 

By CARL H. BUTMAN 

Although the 300-watt radio trans- 
mitter on the "Shenandoah" was dis- 
connected and wet, when she tore loose 
from her mooring mast at Lakehurst 
recently Gunner J. T. Robinson, in 
charge of radio, had his set connected, 
dried and working within an hour and 
sent out a reassuring message to the 
naval air station. 

While the "Shenandoah" was under- 
going her mooring tests, her 300-foot 
aerial was also being tested for capacity, 
inductance and resistance, according to 
Gunner Robinson, who was abroad on 
the wild night trip. The radio appa- 
ratus was disconnected and replaced 



by testing instruments to ascertain the 
efficiency of the present aerial, in an- 
ticipation of installing the newly de- 
signed 1,000-mile set now building at 
the naval radio laboratory at Belleview, 
Md., Mr. Robinson explains. 

When the former ZR-l's nosecap gave 
way, officers and men jumped to con- 
trols, engines and ballast releases, but 
Gunner Robinson, in his radio shack in 
the control car, sprang to his set. Tear- 
ing loose volt-meters, ammeters and 
other testing instruments, he began 
hooking up his transmitting and receiv- 
ing sets, so as to establish communica- 
tion with the home station. But he 
found his apparatus was wet from the 
driving rain and had to dry it all out 
before he could use his phones or key. 
In less than an hour he had his set work- 
ing, but it was not an SOS that he sent, 
as most sea craft would have been forced 
to do under the circumstances — he 
ticked off a message that the "Shenan- 
doah" was under control, which put 
at rest any fears the navy may have had 
and allayed alarm among the families 
of the officers and men. 

Out of the silent darkness came o 
call for NERK, the "Shenandoah's" 
radio call. It was WOR, at Newark, 
giving him his first position report, 
verified later by Lakehurst. The navi- 
gators then knew where the gale was 
driving their ship. 

"Communication was then good for 
the remainder of the trip," says Gunner 
Robinson. "We kept the base well in- 
formed and they gave us weather data," 
he adds, summing up his brief description 
of an unprecedented experience fraught 
with great danger. 

It is evident that radio had consider- 
able to do with the remarkable naviga- 
tion of the aerial cruiser, in advising of 
her safety, and in bringing in reports 
from her base. The reports from NERK 
came through especially well, as the air 
had been cleared for this mobile station, 
which proved indeed mobile. 

The old set, now almost historic, will 
soon be replaced with long distance and 
medium range transmitters, ultra mod- 
ern receiving sets, and a radio compass 
for use in the Arctic explorations. 




Figure i 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



21 



Whistling Interference — Causes and Effect 

By JOHN V. L. HOGAN 



In the ninth of his series through WEAF 
John V. L. Hogan, former president of 
the Institute of Radio Engineers and author 
of "The Outline of Radio," discussed 
"Whistling Interference — Its Causes and 
Cures." In the course of his remarks he 
said: 

THERE are two kinds of whistling 
interference. Both are caused in 
the same general way. One kind 
sounds, in the telephones or loud speaker, 
like a high note of practically constant 
pitch and strength. It may quaver a 
little in pitch and may gradually increase 
or decrease in intensity or in pitch, but 
the sound is generally an almost uniform 
high note. If you listen to distant sta- 
tions on the 833 kilocycle (360 meter) 
wave you have often heard such a uni- 
form whistle in the background. Some- 
times it is not strong enough to prevent 
fairly good reception, but whenever you 
can hear it you may expect the quality 
of music or speech to be partly or wholly 
spoiled by it. 

This kind of whistle is almost always 
caused by interference from a distant 
broadcasting transmitter that has acci- 
dentally changed its wave frequency, 
For example, let us suppose that you 
are listening to WEAF, whose normal 
wave frequency is 610 kilocycles. If 
WOC, in Davenport, Iowa, is sending 
at its proper wave frequency of 620 



kilocycles it will not interfere. But if 
(as has happened once or twice) WOC's 
wave frequency should drop to say 613 
kilocycles, there would be a whistle in 
the background of each station's pro- 
grams. People living about half way 
between the two stations might hear 
cross-talk in addition to a very loud 
whistle, people who were too far from 
either one of the stations to hear its pro- 
grams, but who could hear the other, 
would be troubled by the whistle. 
Key of Whistle 

If the waves of the two interfering 
stations are, as we have assumed, 610 
and 613 kilocycles, the whistle that is 
heard whenever both waves are received 
has a pitch of three kilocycles or 3,000 
cycles. This corresponds to the highest 
G on the piano keyboard. The whistle 
is always of a pitch equal to the difference 
in the frequencies of the two interfering 
waves, as in this case where 613 kc minus 
610 kc equals three kilocycles, i 

As another example we may consider 
whistling interference between WJZ in 
New York and WJAZ in Chicago. These 
stations normally^use waves of 660 and 
670 kilocycles, respectively, and the 
difference of ten kilocycles is enough 
to prevent a troublesome whistle. But 



on some occasions either or both waves 
have slipped away from the normal 
frequency, if they became, for example, 
662 and 664 kilocycles, the difference 
would be only two kilocycles or 2,000 
cycles and the whistle would have the 
pitch of the third C above middle C on 
the piano. 

Interference of this kind, where two 
inaudibly high frequency waves (such 
as radio waves of 610 and 613 kilocycles) 
interact to produce an audible frequency 
equal to their frequency-difference, is 
called beat or heterodyne interference. 
A quite similar effect is had in music, 
for if two sounds of almost equal pitch 
or frequency are played together, their 
waves will interact to produce pulsations 
or beats at a rate equal to the difference 
in their frequencies. 




RADIO ANNOUNCER 

"Billy," a prize white rooster owned by J. O. Maland of the Northwest Farmstead, is a "regular" radio broad- 
casting station announcer. Mr. Maland is in charge of the Northwest Farmstead's lecture hour program at WLAG, 
Twin City Radio control operated at St. Paul and Minneapolis by the Cutting & Washington Radio Corporation. 
A lusty crow from "Billy" into the microphone announces that the lecture hour is about to begin. He also signs 
off with another crow. 

"Billy" receives letters from chickens all over the United States, and presents, consisting of corn, apples, pies, 
etc. 



22 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



Listeners Should Act 

Constant-pitch whistling interference 
caused by interfering broadcasting trans- 
mitters is becoming more and more 
scarce, for most of the stations are doing 
better in holding to their assigned wave 
frequencies. The only cure for it is to 
keep the stations adjusted to radiate 
their correct wave frequencies, and there 
is nothing that either you or I can do to 
stop such cases as 
do occur except to 
report them to the 
broadcasting sta- 
tion that is inter- 
fered with. If it 
were not for the 
fact that this inter- 
station whistling is 
so much like the 
second kind of 
whistling interfer- 
ence, and so con- 
venient for ex- 
plaining it, I 
would not have 
been justified in 
giving it so much 
time. 

I hope that the 
foregoing has 
made clear to you 
that whenever 
your receiver picks 
up two continuous 
radio waves whose 
frequencies are 
quite nearly alike, 
you will hear a 
whistling note 
whose pitch is 
equal to the dif- 
ference in the radio 
wave frequencies. 

This brings us 
to the second type 
of whistles, which 
are usually not 
uniform in pitch or 
intensity and 
which are not 
caused by inter- 
ference between 
broadcast trans- 
mitters. These 
whistles change in 
pitch, either uni- 
formly or in jumps 
and sometimes 
slowly and some- 
times so rapidly 
that they sound 
like chirps. Some- 
times they are 
faint in the back- 
ground, sometimes 

so loud that they completely spoil recep- 
tion from nearby stations. 

If you have a simple regenerative 
receiver of any type, you have heard 
just such whistles as you turned the 
tuning knobs. When you have had 
your tickler coupling or your plate 
variometer too far up the scale, you have 
heard a loud whistle in your telephones 
or speaker and have probably noticed 
that you could control its pitch by turning 
your tuning dial. 

I wonder how many of you realize 
that when you hear such a whistle in 
your own set, a whistle that drowns out 



the station you are listening to and whose 
pitch you can control on your own tuner, 
you are making the same kind of inter- 
ference for all your radio neighbors. 

When your receiver whistles in this 
way, it is acting as a miniature trans- 
mitting station. 

The whistle is the same kind of beat 
note that I have already explained, but 
its pitch usually varies because the waves 




MINIATURE RECEIVER 
This interesting miniature radio set was built by Raymond Chassevent, 
a Bronx amateur. Using but one dry cell vacuum tube and a novel hook-up, 
it will receive when using a ground only, no aerial whatever being necessary. 
Chassevent uses a variometer and several fixed condensers, the fixed con- 
densers taking the place of a variable condenser. Each condenser covers one 
broadcasting wavelength, and will bring that wavelength in with maximum 
efficiency. For instance, one condenser will respond to "WEAF" another 
to "WJZ" another to "WOR," etc. The various condensers are cut in and 
out by taps. It is entirely self-contained, dry cells only being used and is 
so small it can be carried about at will. Note method used for mounting 
condensers, allowing extra condensers to be added at will. 

sent out by the oscillating receiver change 

in frequency as tuner knobs are turned. 

Your Neighbor 

To stop a regenerative set from mak- 
ing such interference, you need only 
reduce the tickler or regenerative vario- 
meter dial setting until the receiver stops 
generating oscillations; you can tell that 
it has stopped interfering because you 
will no longer hear the loud whistle. 

Whenever you hear a loud, varying 
whistle of this kind, a whistle whose 
pitch you can not control with your own 
tuner, you may be sure that it is caused 
by some radio neighbor. 



Standing by 

Washington, D. C. — Captain Herbert 
G. Sparrow, USN, commander of the 
U. S. Cruiser, "Tacoma," and four radio 
men were the last to leave this vessel 
wrecked off Vera Cruz recently — and,, 
at the end, four of them were dead and 
the other injured. Old naval traditions 
obtained, not alone through the action 
of the gallant skip- 
per, but through 
the four radio men 
who stood by with 
him in an effort 
to keep radio com- 
munication open. 
While the de- 
tails of the acci- 
dent which killed 
Captain Sparrow, 
Radio men Lusser, 
Herrick and Sivin, 
and injured Chief 
J. V. Cooper are 
not available, Ad- 
miral Eberle, chief 
of operations, says 
he believes all five 
men were in the 
radio shack trying 
to maintain radio- 
phone communi- 
cation with the 
U. S. Consulate on 
shore, which had 
been established 
the preceding day 
on batteries, as the 
dynamos were out 
of action. Then 
the hurricane 
struck the old 
cruiser, whose bow 
was on a reef, and 
threshed her un- 
mercifully, wash- 
ing her with ter- 
rific seas and 
pounding her to 
pieces. 

Either a falling 
mast or an ex- 
tremely heavy sea 
is believed by the 
admiral to have 
crushed in the 
radio shack, for- 
merly the captain's 
emergency cabin, 
located on the 
main deck just be- 
low and aft of the 
bridge. The only 
dispatch bearing 
on the death of 
these four men states: "They all were 
killed on the main deck on January 21, 
struck by heavy wreckage and seas." 

Naval officers picture the captain, 
who was an authority on electrical mat- 
ters and a radio enthusiast, and the radio 
operators, as crowded around the ship's 
radio apparatus trying to send a last 
message to the Vera Cruz Consulate, 
when the crash came. 

Investigations, scheduled as soon as 
the "Prometheus" reaches Charleston 
with the survivors, may reveal that the 
navy has developed a new type of hero 
— the radio man who remains aboard. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



23 



SIMPLEX REFLEX SET 



By CARL MASSON 





A. fT TRANS. 

R/\TI6- fe to I 





.DOOMS' 



- "\3" 8AT -t- 

i.|'|'l'H" 



Figure 2 — Circuit diagram of the simple reflex receiver. 



In spite of the numerous hookups 
which constantly appear in publication, 
should we take a census of the various 
types of sets in use, I feel quite sure that 
the popularity of the Reflex would be 
quite evident. 

The diagram in Figure 1 shows a 
one-tube reflex circuit of unusual effi- 
ciency in respect to both distance and 
volume. While this circuit is by no 
means new but because recently such 
unusually good results have been secured 
with it, I believe too little has been said 
about it. 

The panel should measure 7 inches by 
12 inches. The general layout is shown 
in the illustration herewith. Drilling 
dimensions are omitted, since they 
would vary according to the type of 
apparatus used. The variocoupler is 
mounted to the extreme left. About 
twelve taps are taken at various inter- 
vals and connected to two switches on 
the panel. 








oorp - ,., 

8& f* 



<?T^ 



o r 
o 



The R. F. transformer is of the special 
type manufactured particularly for use 
in reflex circuits. 

The A. F. transformer may be of any 
good make, but should have a ratio of 
six to one. A crystal detector of the 
fixed type would rid the operator of one 
more adjustment. The fixed condensers 
should be of the mica type, with capaci- 
ties as shown in the circuit. Practically 
any tube may be used. Very good 
results have been secured using UV 199. 
The rheostat of course would depend 
upon the type of tube. A radio set is no 
better than its poorest part, therefore 
when you buy your parts let quality 
count. 

Use bus bar in wiring the set, and if you 
would have the utmost efficiency, make 
all connections as short as possible, 
regardless of appearances from artistic 
viewpoints. Solder all connections, tak- 
ing care that all excess flux is removed. 

The tuning of this outfit is extremely 
sharp and selective, but the simple 
controls make operation quite easy. 
Judging from the results that users of 
this outfit report, it is no wonder that 
it has become so popular. The fact about 
this circuit, that one tube does triple 
duty, seems to violate the old adage: 
"You can't run the mill on the water that 
has passed." 



Wireless Tales 



Figure 1 — Panel layout of the 
simple reflex circuit. 



One would scarcely think the sweet 
song of a canary would in any way affect 



the prolongation of the incarceration of 
three of Uncle Sam's sailors in a Japanese 
prison, but so the tale of an ex-navy 
operator goes. Three firemen from the 
good ship, "Orion," got themselves in 
wrong with the Nagasaki authorities 
and were detained ashore, although their 
ship was sailing. Upon the request of 
his captain, the Orion operator called 
the flagship to ask that steps be taken 
to secure the firemen's release and return 
to the States. 

Sparks got his message off, despite the 
fact that a canary he was bringing home, 
sang in harmony with the ship's radio 
wave note. As soon as the operator 
started to listen in for his O. K. the bird 
redoubled its efforts in a key which 
interfered so seriously with the reception 
of the flagship's answer that it made it 
impossible to get the message. Spark's 
couldn't leave his key to put the bird 
out of the shack, so he threw spare parts 
and tools in its general direction, with- 
out effect. Again he called the flagship; 
again the dickey bird, now exceedingly 
unpopular with its temporary owner, 
began its lusty song. As the ship steamed 
out to sea, the operator gave up in de- 
spair; he couldn't get his answer through 
the canary's QRM. It developed later 
that Orion's message was not received 
correctly, and the unlucky firemen were 
held in the Japanese "brig," several 
months, all because of the canary's sweet 
obligato. The bird finished the voyage 
in a stateroom, but when delivered to 
its ultimate owner ashore, although un- 
harmed, it refused to sing again. 



24 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



United States Accuses Radio Trust 



MONOPOLY in the radio appar- 
atus and communication, both 
domestic and transoceanic, is 
charged in a complaint issued by the 
Federal Trade Commission. Efforts to 
perpetuate the present control beyond 
the life of existing patents, is likewise 
charged. 

Radio Corporation of America; Gen- 
eral Electric Company; American Tele- 
phone & Telegraph Company; Western 
Electric Company, Inc.; Westinghouse 
Electric & Manufacturing Company; 
The International Radio Telegraph Com- 
pany; United Fruit Company; and 
Wireless Specialty Apparatus Company, 
are named as respondents and are alleged 
to have violated the law against unfair 
competition in trade to the prejudice of 
the public. 

In the language of the complaint "the 
respondents have combined and con- 
spired for the purpose and with the effect 
of restraining competition and creating a 
monopoly in the manufacture, purchase 
and sale in interstate commerce, of radio 
devices and apparatus, and other elec- 
trical devices and apparatus, and in do- 
mestic and transoceanic radio communi- 
cation and broadcasting." 

To attain the present control alleged, 
the complaint recites that the respond- 
ents: (1) acquired collectively, patents 
covering all devices used in all branches 
of the art of radio, and pooled these 
rights to manufacture, use and sell radio 
devices, and then allotted certain of the 
rights exclusively to certain respondents; 
(2) granted to the Radio Corporation of 
America, the exclusive right to sell the 
devices controlled and required the Radio 
Corporation to restrict its purchases to 
certain respondents; (3) restricted the 
competition of certain respondents in the 
fields occupied by other respondents; (4) 
attempted to restrict the use of apparatus 
in the radio art manufactured and sold 
under patents controlled by the respond- 
ents; (5) acquired existing essential equip- 
ment for transoceanic communication 
and refused to supply to others neces- 
sary equipment for such communication; 
and also excluding others from the trans- 
oceanic field by perferential contracts. 
2,000 Patents Involved 
From the series of contracts referred 
to in the complaint it appears that the 
Radio Corporation of America has the 
right to use and sell under patents of the 
various respondents which relate to the 
radio art. It has also given to various 
respondents the right to manufacture 
under these patents. Thus there has 
been combined in the hands of these cor- 
porations patents covering the vital im- 
provements in the vacuum tube used in 
long distance communications and other 
important patents or inventions in radio 
which supplement this central device. 
Approximately 2,000 patents are in- 
volved. 

The report of the federal trade com- 
mission on the radio industry states that 
the gross income of the Radio corpora- 
tion in 1922 was S14, 830,856 and that its 



capital stock on Dec. 31, 1922, was $33,- 
440,033. The holdings of the several 
respondents in the Radio Corporation of 
America are given as follows: General 
Electric company, 620,800 preferred, 
1,876,000 common; Westinghouse Elec- 
tric and Manufacturing Company, 1,- 
000,000 preferred, 1,000,000 common; 
American Telephone and Telegraph com- 
pany, 400,000 preferred, no common; 
United Fruit company, 200,000 preferred, 
160,000 common. 

It is further stated that up until 1922, 
the Radio Corporation had an absolute 
monopoly in the manufacture of vacuum 
tubes and for the first nine months of 
1923 sold 5,509,487 tubes. During the 
same period the only other concern hav- 
ing the right to make and sell tubes, sold 
94,100 tubes. 

In the communication field, while the 
Radio Corporation has some competi- 
tion in ship-to-shore communication, it 
has a practical monopoly in trans- 
oceanic service. It controls all the high 
power stations in this country except 




WILSON FUNERAL 
When former President Woodrow 
Wilson's funeral service was held in 
Mt. Alban's Cathedral, Washington, 
D. C., radio transmitted the sermon 
to the whole country. Photo shows 
the microphone on the pulpit. 



those owned by the United States gov- 
ernment. Agreements of an exclusive 
character have been entered into with the 
following countries or with other con- 
cerns in control of the situation in those 
countries, namely, Norway, Germany, 
France, Poland Sweden, Netherlands, 
South America, Japan and China. Ar- 
rangements have also been made with the 
land telegraph companies in this country 
whereby messages will be received at the 
offices of the Western Union and Postal 
Telegraph companies. 

The Contracts 

A summary of the contracts between 
the respondents as recited in the com- 
plaint is: First, the organization of the 
Radio Corporation of America in 1919, 
under the supervision of the General 
Electric Company, which company re- 
ceived large holdings in the stock of the 
Radio Corporation for capital supplied 
and for its service in connection with the 
acquisition of the American Marconi 
Company. An agreement entered into 
between these companies granted to the 
Radio Corporation an exclusive license 
to use and sell apparatus under patents 
of the General Electric Company until 
1945; and the Radio Corporation granted 
to the General Electric Company the 
exclusive right to sell through the Radio 
Corporation of America only, the corpora- 
tion agreeing to purchase from the Gen- 
eral Electric Company all radio devices 
which the General Electric Company 
could supply. Subsequently this ar- 
rangement was extended to include the 
Westinghouse Electric & Manufacturing 
Company, the business of the Radio Cor- 
poration being apportioned between the 
General Electric Company and the West- 
inghouse Company; sixty per cent to the 
General Electric and forty per cent to the 
Westinghouse Company. 

Meanwhile in July, 1920, the General 
Electric Company, and the American 
Telephone and Telegraph Company, 
made an arrangement for mutual licens- 
ing on radio patents owned by each and 
providing for traffic relations. The terms 
of this agreement were extended to the 
Radio Corporation of America and the 
Western Electric Company and thereafter 
to the Westinghouse Company. 

The Radio Corporation in March, 
1921, made an agreement with the United 
Fruit Company, which operated a number 
of long distance radio stations in Central 
and South America by which licenses un- 
der radio patents of the Radio Corpora- 
tion and of the United Fruit Company 
and its subsidiary the Wireless Specialty 
Apparatus Company, were exchanged, 
and arrangements made for the exchange 
of traffic facilities, and the definition of 
their respective fields adopted between 
the Radio Corporation and the United 
Fruit Company. Provisions of the agree- 
ments between the Radio Corporation of 
America, the General Electric Company, 
the American Telephone and Telegraph 
Company and the Western Electric 
Company were extended to the United 
Fruit Company. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



25 




1^ JHclc 
Hoolc 

^iytf ottr- A 




SOME time ago I made it a point to 
call upon the Editor of RADIO 
AGE, with the object of finding out 
how much space he was going to allot for 
the Pickups by Readers Department, 
in this issue of RADIO AGE. 

Upon entering the Editor's office I 
was told .to take a chair and to wait 
patiently for a few moments inasmuch as 
the Editor was rather busy, but would 
see me shortly. 

"He's probably pondering over some 
deep and important editorial problem or 
advertising policy," I mused as I took a 
chair, depositing a stack of Dial Twister 
letters on a nearby table. "I suppose it 
takes much thought and deliberation to 
decide just what department to em- 
phasize to make a first class radio book 
such as RADIO AGE is." 

After a short wait, I was told to step 
into the Editor's 
den and I'll bet 
you can't guess 



all those letters from Pickup fans?" he 
asked. 

"That's what they are nothin' but," 
I answered quickly. 

The Editor pondered deeply for a few 
moments, puffing vigorously on a black 
cigar, and then turning back to his record 
comparing in the Pickups section of the 
preceding RADIO AGE he muttered: 

"Ummmm! If the fans like 'em as 
well as I do, they must get a pretty 
big kick out of them!" 

And looking up he decided: 

"Let 'em run freely. Understand? 
If you've got enough of them let 'em 
run freely. And by the way, when you've 
finished compiling them and got them 
in copy form, I want to be the first one 
to read that copy — I get just as big a 
kick out of them as a nigger does reading 
ghost stories ten minutes before bedtime. 



what 
was 
over! 
He 



the Editor 
pondering 



DIAL TWISTERS 



had a Feb- 
ruary RADIO 
AGE opened to 
the page which 
had a heading over 
it, "Pickups by 
Readers," and was 
comparing the list 
of stations heard 
on his receiver 
with one of the 
letters and lists 
submitted by a 
Dial Twister! 

"You know," he 
said, "I've got one 
of the best types 

of receivers on the market. I've got all 
the batteries and accessories pepped up 
to the nth degree. I've sat up until the 
wee hours of the morning, until I've got- 
ten a taste in my mouth like a black- 
smith's apron; but I'll be hanged if I can 
beat that record submitted by one of 
these Dumbell Twisters or whatever you 
call them!" 

"Ha!" I laughed, "You're only one of 
the many, many fellows who are doing 
the same thing, trying to beat a record 
or list of some Dial Twister." And 
feeling sure that he would kick the 
Pickups by Readers section out of his 
magazine forever because he couldn't 
beat one particular Dial Twister record, 
I added, "Do you think that you can use 
about a page and one-half of these 
(dashing down a pile of Dial Twister 
letters on his desk) in the March issue?" 

"For the love of barb-wire antennas 
and oscillating circuit receivers — are 



Name Address Circuit 

John Sibiston, Jr Bay Shore, L. I., N. Y Atwater-Kent 

Curtis Springer 1224 N. Olney St Single Circuit 

Kenneth Fischer _ 1219 N. Olney St Single Circuit 

Both of the above TWISTERS live in Indianapolis, Ind. 

Russel R. Thomas.. 227 Laurier Av., W., Ottawa, Ontario, Can Haynes 

Frank P. Oberst Racine, Wisconsin Single Circuit 

Richard Jones 300 N. Warner Av., Bay City, Mich., Corrected from last month 

George S. Everhart ..._ 4214 Ruckle St., Indianapolis, Ind Eliminator 

Charles E. Rogers ;_ 4409 N. Lincoln St., Chicago, 111 Eliminator 

H. S. Frederickson ..._. 406 Howard St., Charles City, la Ultra-Audion 

Joe Hafert.._ 1323 Woodbine PI., Ft. Wayne, Ind _ Reinart". 

Wilson B. Lemberger 2037 Osborn St., Burlington, la _ Zenith 

H. A. Englebaugh 1328 Winona St., Chicago, 111. Eliminator Crystal 

G. S. Baird __ 32 Maltbie Av., S iffern, N. Y Erla-Triplex 

Frank W. Smith _ 2306 Edward St., St. Joseph, Mo ReinartJ 

Max M. Barnhl er.. Mt. Morris, 111 _ First Tube 

H. J. Boyenga Greene, la. Reinarf. 

J. H. Jones Crestwood, Ky Cockaday 

Francis Tye 607 N. 8th Av.. Maywood, 111 _ Rosenbloom 

A. W. North.. 61 N. Lincoln Av., Fond du Lac, Wis First Tube 



Don't slam the door as you go out." 

And so I'm letting 'em run freely, to 
the extent of a couple of pages or so. 
THE PICKUPS EDITOR. 



John Sabiston, Jr., of Bay Shore, 
Long Island, wants to start out this 
month by hanging a bakelite crepe on 
the lists of Curtis Springer, Kenneth 
Fischer and his neighbor John Bennett of 
Rockville Centre, Long Island, N. Y., 
and submits the following to substantiate 
his claim: 
RADIO AGE, 
Gentlemen: 

I am a regular subscriber to your 
magazine, and I take great pleasure in 
reading the Pickup Page. I notice the 
excellent pickups of Curtis Springer, 
Kenneth Fischer and my close neighbor 
John Bennett of Rockville Centre, and 
want to say that while I think their 
records are good, I feel that I have a list 



that will equal if not surpass them all. 
I have an Atwater-Kent three tube 
set that I wouldn't sell for all the sets on 
the market. Getting down to business, 
here is my list of stations heard from 
January first to February ninth, prac- 
tically all of them on a loudspeaker. 
As one would say when playing dice: 
"Read them and weep!" 

KDKA, KFKX, KOB, KOP, KSD, 
KYW, PWX, WAAF, WAAW, WBAH, 
WBAP, WBT, WBS, WBAU, WBZ, 
WCAE, WCAP, WCBD, WCX, WDAR, 
WDAF, WDAP, WDAY, WDT.WEAF, 
WEAN, WFAA, WFAY, WFI, WGI, 
WGR, WGY, WHAM, WHAS, WHAZ, 
WHB, WHN, WIP, WJAR, WJAX, 
WJAZ, WJZ, WJY, WKAQ, WLAG, 
WLW, WMAF, WMAQ, WNAC, WOS, 
WOAW, WOC, WOO, WOR, WPAB, 
WPAH, WRC, WSAD, WSB, WTAS, 
WTAM, WSAI, 
WWJ, WQAM, 
WCAD, WMAK, 
WCAL, WSY, 
WIAD, WFAB, 
WCE, WHAA, 
N P G , N R E , 
CFCA, KGO, 
W M C , W B L , 
6 K W , W H K , 
KFAF, CKCK, 
CKAC, CHCB, 
CHYC, CFCF, 
CJCN. 

Besides this 1 
got a complete 
test from station 
9BM of Canada, 
on the night of 
January 8, from 
12:15 to 1:36 a. m. 
On this test they 
broadcast on the 
following wave lengths: 400, 300, 350, 450 
500,550, 341, and I was waiting for them 
every time they came on. What do you 
consider this? 

I am a great radio bug, and I would sit 
up till five a. m. if they broadcast that 
long. 

I trust that you will give my record 
due consideration, and hope expectantly 
to see my name on the Dial Twisters 
list for next month. What say? 
Very sincerely yours, 

JOHN SABISTON, JR. 
Bay Shore, Long Island, N. Y. 
All we've got to say is — wait till the 
Editor reads that one! That's what we 
would call a record for consistent work, 
Johnny, and you've certainly made the 
DT list. 



However, judging from the appear- 
ances of this correspondence you'll have 
one extra bakelite crepe to hang on 



26 



RADIO AGE— "THE MAGAZINE OP THE HOUR' 




EUM/UATOR 



^ 



VAQ/fltil* 
CONQSMSER. 



6QWAJD 



Figure 1. This shows^the connections~\of the Eliminator used as a crystal receiving 
set tuner, with which Mr. Englebangh claims such unusual results. LI is the primary 
of the Eliminator, and consists of from 8 to 12 turns of No. 24 or 26 DCC wire; L2 is the 
secondary, consisting of about 42 turns of the same size wire, which is shunted by a con- 
denser of either 23 or 42 plates. The size of wire is not important. The primary is wound 
directly over the secondary, being separated by a layer of empire cloth or writing paper. 
Full details of the original Eliminator were published in the January, 1924, issue. 



your own record, because, because — 
well just read this: 
RADIO AGE, 
Gentlemen: 

We are very much interested in your 
Pickups Page, and have a record which we 
think will put us nearer the top in the 
DT list. 

On Saturday night (our friends don't 
state what Saturday) using a three tube 
single circuit set, we made a little record 
for a single night. Fifty-eight all told! 
The list is: WHAS, WSB, KDKA, 
BI6, BI4, WJAK, 9ESI, WBZ, WCAE, 
WDAP, WDAF, WWJ, 9WE, 9VC, 
WJAR, WGY, WPAB, WEAF, WCK, 
WLAX, WCBD, WOS, WTAQ, WOC, 
WRC, WHN, KFSB, WDI, WGR, 
WMC, KSD, KYW, WOAW, WDAR, 
VVBAV, KFKB, WSAH, WJAZ, WBAP, 
KHJ, 5ST, VVTAS, KFKX, 1XU, WLAG 
WIAI, 9XAT, WHAA, KFAE, 9QI, 
KFSG, KFI, 5ZG, 9ANY, KGW, WAAW 
WTAM and also Kalia, Cuba. 

The Cuban station said they had no 
call letters yet. They broadcast on 360 
meters. 

Since December twenty-seventh 1923 
to February eighth, 1924, we have heard 
all told two hundred four different 
stations, most of the time only using two 
tubes. Try to beat that! 

(Here is where the joke comes in — 
read the names carefully, and then laugh! 
—[The Editor.) 

Yours very truly, 
CURTIS SPRINGER, 

1224 N. Olney St., and 
KENNETH FISCHER, 
1219 N. Olney St., 

Indianapolis, Ind. 



Mr. Sabiston — If you'll take our 
advice, don't try to beat that. These 
kids get the wooden ohm-saw for the 
month. Your letter came just in time 
DT's and what a timely defense you 
present yourselves with! 



Now we are all, without doubt, inter- 
ested in that Haynes circuit published in 
the December, 1923, issue of RADIO 
AGE, and we have a lot of letters of fans 
who want addresses of other DT's that 
are getting results so that they can 
compare records. Here's a letter that 
puts the Haynes on the Dial Twister's 
list: 

RADIO AGE, 
Gentlemen: 

I am writing to let you know of the 
success I have had with your Haynes 
DX hookup as published in the Decem- 
ber, 1923, issue of RADIO AGE. With 
detector and one stage of audio frequency 
amplification with a Canadian tube as a 
detector and a WD 12 as amplifier, I 
have heard as many as thirty-two 
stations in a single night on a loud speak- 
er unit consisting of a Baldwin type C 
phone with a table talker, which by the 
way is home-made. 

Most of these stations are around the 
1000 mile mark. Last Thursday night 
(January 31) I picked up WKAQ, San 
Juan, P. R. on the loud speaker and held 
him for three quarters of an hour! 
Tonight (February 7) I went after him 
again and got him right off the bat on 
the same place on the dials. I have a 
list here that says that WKAQ is silent 
on Thursday nights, but that can't be 
so, as several of my friends with larger 
sets picked him up also. 



I log all my stations and never find 
them to vary over five degrees of the 
vernier. I intend to add two more stages 
of audio, and if the police allow me I will 
be tuned in every night. And as Jack 
Nelson of Willy Dapp (WDAP) says, 
"That's that!" Very truly yours, 

RUSSELL R. THOMAS. 



227 Laurier Avenue West, 
Ottawa, Ontario, Canada. 
Mr. Thomas wants to know if two stages 
of radio frequency can be added to the 
Haynes, and wants to know if we have a 
diagram. Frankly we tell you that as yet 
we have no diagram that has been 
actually tested out to give results, but 
feel quite sure that it could be added to 
the Haynes much in the same way as to 
the Reinartz, with the exception that the 
tickler coil would probably, have to 
be changed a little. Are there any experi- 
menters who can help him out? We 
would suggest that you add the push-pull 
amplifier as described in January instead 
of the radio frequency as you will then 
be blessed with greater volume and still 
retain the benefits of a straight regenera- 
tive circuit. To tell the truth, we are not 
inclined to recommend radio frequency 
with highly regenerative circuits due to 
the fact that it is quite a problem for the 
average dial twister to engineer his set 
to get the best results. And if you don't 
use radio frequency in the right way, 
you wont get much satisfaction. 



And as the barber says, ''Next!" 
RADIO AGE, 
Gentlemen: 

After reading some of the letters of 
the February Pickups Page, I decided 
to write and let you know what my single 
tube single circuit set is doing. 

On a good night I have no trouble 
tuning in from thirty to forty stations 
and hear them with surprising volume 
and clearness. Among those I have 
heard are KHJ, KPO, KFDL, WFAA, 
WDAT, WDAJ, WJAR, CKAC, WEAF, 
WIP, WSB, KDKA, WSY, WCAP, 
WOR, WMC, KSD, WCAE, WHAS, 
WHAM, WHN, KFKX, WOAW, WWJ, 
KOP, WBZ and others. 

On December twenty-eighth I tuned in 
forty-eight stations and all together I 
have heard 111 different stations. I am 
using a WD 12 tube on my set. 

To RADIO AGE, "The Magazine of 
the Minute" (not hour) I wish good luck. 
Very truly yours, 
FRANK P. OBERST, 

Racine, Wisconsin. 

We note, Frank, that you are only- 
using one tube, and are pleased to say 
that you have results almost equal to 
the record established by Ken Fischer 
and Curt Springer in this issue, who, 
while they have a hot record, honestly 
state that they use two and three tubes. 
There is one thing sure and that is, Mr. 
Sabiston can't nail that bakelite crepe 
on your record. HI! 



By the way, fellows, I suppose many 
of you had orders in for the RADIO 
AGE ANNUAL that big fat book full of 
the latest dope and circuits and had to 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



27 



wait quite a while before your orders 
were shipped. We wonder if you felt this 
way about it: 
RADIO AGE, 
Gentlemen: 

I received your card acknowledging 
my dollar saying that the book would be 
sent me as soon as it came off the press! 
For the LUVAMIKE has the press 
busted? When do you think I wanted to 
build the set? I'd like to have it before I 
die of old age. 

Let me hear from you soon — don't 
keep me in this awful suspense. 
Respectfully, 
L. A. CASS, 
6446 Ellis Ave., Chicago, 111. 

Mr. Cass has no doubt built his set by 
now and is enjoying the comprehensive 
contents of the Annual, but that doesn't 
stop us from making the remark that 
Dial Twisters are probably the most 
impatient people in the world. As the 
indulgent mother said to her son, who 
was crying because the theatre he had 
just been rescued from caught fire, just 
as the play in progress was nearing the 
climax: "Patience, Alfonso, patience! 
They will resume the play as soon as the 
theatre is rebuilt!" 



And seeing that we are inclined to 
print a few kicks this month, we also 
print this one: 
RADIO AGE, 
Gentlemen: 

My list appeared in your February 
number but due to some error on your 
part my name on the Dial Twisters list 



was followed by "Milwaukee, Wisconsin." 
I wish to thank you for placing me on the 
list and also ask you if you will please 
correct this error. 

Since writing you I have added many 
stations to my list and want to add the 
following over 1000 miles: WNAD, 
KGW, KLX, WDAH, the first being 1000 
miles away, the second 2100, the third 
2300 and the last only 1700! 

Please do not think me a "limelight 
bug" but I would like to see a record 
held by anyone on a single tube set that 
beats mine. If you can find just a little 
corner in your excellent department will 
you please give my correct address and 
state that I will gladly give all data and 
hookup of my set to anyone writing me. 
I would like to see everyone in the U. S. 
A. get just as good results as I am on my 
set. And everyone can, too. 

I think that your Dial Twisters' 
idea is a splendid one; it makes you feel 
pretty good to see your name on a list 
like that after working into the small 
hours of the morning to get up a list. 
I am not able to decide an appropriate 
compliment for RADIO AGE. 

Thanking you for publishing my list, 
I am, Yours very truly, 

RICHARD JONES. 

P. S. After writing this I read the 
lists by the youngsters in their "teens." 
Well, as far as that goes I'm only seven- 
teen but like everyone else (although 
they don't like to admit it) I enjoy the 
bedtime stories too, especially if they 
come from a station two or three thou- 
sand miles from here. 



And now Mr. Printer, please put this 
address in italics. If we know what's 
what, Mr. Jones is going to be swamped 
with letters because I have already had a 
number of requests for his address: 
Richard Jones, 300 North Warner Avenue, 
Bay City, Michigan. 

Also, 'Dick, RADIO AGE lives at 500 
North Dearborn St., Chicago, 111., and 
not at Mount Morris, 111. Mount 
Morris is only the place where RADIO 
AGE is printed. (That last remark has 
all the earmarks of a comeback, eh, wot?) 

Due to the fact that "Variety is the 
spice of life," we won't let this whole 
department be filled with kicks, so we're 
going to print a couple of renditions 
entitled, "Of all my wife's relations, I 
love myself the best." 
RADIO AGE, 
Gentlemen: 

Tried out your eliminator as described 
in January, 1924, of RADIO AGE. 
It works fine. It certainly is an aid in 
tuning. Tell the fellows that they might 
get better results by winding it with 
number 18 SCC wire. 

Last night my variocoupler went on the 
bum. I disconnected the coupler and 
used the eliminator as a fixed tuner, the 
8 turns as primary and the 40 turns as 
secondary. It worked better than any 
coupler I have ever used. IT BROUGHT 
IN KHJ ON THE LOUD SPEAKER! 
Yours truly, 
GEORGE S. EVERHART. 
4214 Ruckle St., Indianapolis, Ind. 

This is RADIO AGE broadcasting; 




A CAGE ANTENNA 
A new type of radio enthusiast has made his appearance in Robert McAffee's home on West End Ave., N. Y. 
He is none other than the family's pet parrot, "Jake." He is so interested in radio that he calls out all local and 
distant stations by heart. He is also so familiar with the voices of the various radio announcers that he is constantly 
imitating them. He wants to do his part so he permits his cage to be used as an aerial. 



28 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



stand by one moment. Our next number 
will be a barber-shop rendition of the 
parody on "You Can Take Me Away 
from Dixie," etc., entitled "I can tune 
out stations in Chicago, For interference 
I don't give a rap. 'Cause in series with 
my antenna, I've got a RADIO AGE 
WAVE TRAP," sung by Chas. E. 
Rogers, accompanied by the Pickups 
Editor on a squealing, howling, oscillating 
and yowling ten tube neutrodyne. Let's 
go! 



RADIO AGE, 
Gentlemen: 

Broadcasting advertising pays. Had 
it not been for WJAZ the Edgewater 
Beach Station announcing one Sunday 
night that your RADIO AGE contained 
some very interesting hookups along the 
wave trap line for eliminating stations 
not desired, I would not have thought of 
buying one of your magazines; but upon 
hearing this in the air, I at once went to 
three or four stores to purchase one; and 
you can rest assured that I will not miss 
a single copy from now on, as your book 
is without question the best of its kind 
on the market to-day as far as radio is 
concerned; and as soon as some of my 
subscriptions are up on some of the other 
magazines I intend to be a yearly sub- 
scriber for yours. 

I constructed the wave trap on page 5 
of your January issue and tried it out 
last night while the opera was on from 
KYW and WDAP, the Board of Trade 
Station and the Daily News WMAQ, 
and must compliment you on your in- 
formation. Between the hours of 7:30 
p. m. and 10 p. m. this wave trap cut out 
the Chicago stations and I was able to 
pick up WHAS, Louisville, Ky.; WTAS, 
Elgin, 111.; WGY, Schenectady, New 
York; WHB, Kansas City, Mo.; KDKA, 
East Pittsburgh, Pa.; WDAF, Kansas 
City, Mo.; KSD, St. Louis, Mo.; WOR, 
Newark, New Jersey; WJAX, Cleveland, 
Ohio, and VVEAF, New York City, 
New York. I think this is a very good 
record for a one tube set with the assis- 
tance of your wavetrap. I intend to 
construct the last-mentioned trap and 
see if that will render me any better 
service than the first- mentioned one, 



*v 



AERIAL 



. CXDOS'filF 



rp 



1-3 MBGOHMS 
.O0O5~~MF' 




YA&QME7£g 



although I am more than pleased with the 
results, and want to thank you for being 
able to receive such good and valuable 
information for such a small cost as 
twenty-five cents, the price of your 
magazine. 

Yours truly, 
CHARLES E. ROGERS, 
4409 N. Lincoln St., Chicago, 111. 
Knowing how hard it is to tune out 
Chicago stations when trying to get a 
DX program, we are putting Mr. Rogers 
name on the DT list, as it is a real accom- 
plishment. Maybe not from a standpoint 
of distance or consistent work but for 
doing something that was formerly 
claimed that only a superheterodyne 
with a special oscillator could do. 
Good work, Mr. Rogers. 



At last we have a fellow who has ap- 
parently got a list that compares with 
Ken Fischer and Curt Springer's records, 
in respect to the number of stations heard. 
He only misses their single night record 
by eight stations, but beats their agg r e- 
gate number by a considerable figure. 
RADIO AGE, 
Gentlemen: 

I am a constant reader of RADIO 
AGE and so I'm naturally interested in 
the Pickups Department. 

I have noticed for some time, the 
records of BCL's from all over the coun- 
try, but as yet I've seen nothing that 
beats mine! Therefore I think I'll "tell 
the world" about my record. Beat it if 
you can! 

I have a home-made detector, and two 
step using the ultra Audion hookup. 
My antenna is a plain single wire about 
90 feet long, strung between two trees. 

My total number of stations to date is 
251, with an aggregate Mileage (i. e. from 
my set to each station) of 169,111 miles. 
This includes stations from Canada, 
Mexico, Cuba, and Porto Rico. 

Last night, January 25, I played a 
game of radio golf, or in other words, I 
tried to see how many different stations 
I could get in one evening. I put on the 
Baldwins at just 6:45, and when I quit at 
10:45, I had a list of 50 different stations 
that I had heard during that four hour 
period. 





F/X£0. 001 
—WMJ V£RNI£R ZUeoXtiT 



■8 BAT. 



Figure Z. A simple single circuit regenerative set, -with which one of the DT's gets 
such good results. Fellows having trouble with the Rosenbloom might give this one a twirl. 



Here is the list. If any one doubts it, I 
have the exact time of hearing each sta- 
tion, to prove it: 

*1 WAAN, Columbia, Mo. 

*2 VVJAK, Greentown, Ind. 

3 WGY, Schenectady, N. Y. 

4 KDKA, Pittsburgh, Penn. 

5 WDAP, Chicago, 111. 

6 WHAS, Louisville, Ky. 

7 WCK, St. Louis, Mo. 

8 KFKB, Milford, Kans. 

9 WHB, Kansas City, Mo. 

10 WOAW, Omaha, Neb. 

11 WMAQ, Chicago, 111. 

12 KYW, Chicago, 111. 

13 WCAE, Pittsburgh, Pa. 

14 WBAP, Ft. Worth, Tex. 

15 WRC, Washington, D. C. 

16 WHA, Madison, Wis. 

17 WSB, Atlanta, Ga. 

18 WOC, Davenport, Iowa. 

19 WMC, Memphis, Tenn. 

20 WEAF, New York City. 

21 WLAG, Minneapolis, Minn. 

22 WJAR, Providence, R. I. 

23 WBAV, Columbus, Ohio. 

24 WJAD, Waco, Texas. 

25 WCAL, Northfield, Minn. 

26 KLZ, Denver, Col. 

27 WTAS, Elgin, 111. 

28 WCBD, Zion, 111. 

*29 CHYC, Montreal, Canada. 

30 WDAR, Philadelphia, Pa. 

31 WOS, Jefferson City, Mo. 

32 KHJ, Los Angeles, Calif. 

33 WJY, New York City. 

34 WDAF, Kansas City, Mo. 

35 CKAC, Calgary, Canada. 

36 CKCK, Regina, Canada. 

37 WFAA, Dallas, Tex. 

38 WOO, Philadelphia, Pa. 

39 WJZ, New York City. 

40 KFAF, Denver, Colo. 

41 KFAE, Pullman, Wash. 

42 WNAD, Norman, Okla. 

43 KFDY, Brookings, S. D. 
*44 KQV, Pittsburgh, Pa. 

45 WJAZ, Chicago, 111. 

46 KFI, Los Angeles, Calif. 

47 KFEL, Denver, Colo. 

48 WJAQ, Topeka, Kan. 

49 KGW, Portland, Oregon. 
*50 CYL, Mexico City, Mexico. 

(The star means new station.) 
Well — can any one beat it? If they 
can let's hear 'em broadcast. 
Yours very truly, 
H. S. FREDERICKSON, 
406 Howard Street, 
Charles City, Iowa. 
The editor will wear warts on his 
fingers when he tries to beat that one. 
In the meantime, Mr. Sabiston still 
has an extra bakelite crepe that he is 
trying to get rid of at 66 3-4 per cent off. 
HI! 



And here's a fellow who gallantly 
defends the Reinartz! 
RADIO AGE, 
Gentlemen: 

I have not heard much from Reinartz 
owners, therefore I am sending in my 
list of stations for the month of January. 
I put my set together December 31, set 
it up on January 1, and the stations I 
have received since then are as follows: 
KDKA, WGY, WOC, WFAA, WLW, 
WHAS, WGR, WCAD, KFKX, WJAX, 
WMAK, WTAS, WDAP, WHD, WOS, 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



2!) 



WLAG, WLAX, WSAI, WDAF, KYW, 
WBZ, WHAZ, WPAM, WCAL, KLZ, 
WMC, WSB, WNAD, WJAZ, WCK, 
VVVVJ, WRW, CFCA, WOAW, WBAP, 
WTAM, WOAI, WCAM, WCBD, WOR, 
WPQB, WBBD, WEAM, WMAQ, 
WJAD, KFKB, 9AMJ, 9AFY, 9ALW, 
9AFA. The last four are amateur radio 
telephone stations. 

I think my little one-tube Reinartz 
makes a close stab for the record this 
month. All fifty of the stations came in 
very clearly. Would like to hear from 
some of the other Reinartz bugs. Write. 
Respectfully, 

JOE HAFERT. 

1323 Woodbine Place, Fort Wayne, Ind. 

By golly, if you could catch fifty 
stations in the first month you had your 
set up, you are a pretty apt learner in 
the matter of learning to tune, and we„ 
are putting your name on the DT list. 
Usually it takes about a month or two 
before a fellow learns to get his first DX 
station. 



And here's another fellow who makes 
the grade of Dial Twister because his 
work for one evening is commendable. 
RADIO AGE, 
Gentlemen: 

I am submitting the following list 
of stations as logged by me on November 
26, 1923, using a Zenith detector and 
two-stage audio frequency amplifier. 
Homemade. 

I believe that this list entitles me to 
membership in your much prized "Order 
of Dial Twisters." 

WCX, Detroit, Mich., KDKA, East 
Pittsburgh, Pa., WBZ, Springfield, Mass., 
WCAE, Pittsburgh, Pa., WLAG, Minn- 
eapolis, Minn., WOO, Philadelphia, Pa., 
WWS, Detroit, Mich., WEAF, New 
York City, N. Y., WBAP, Ft. Worth, 
Texas, WDAF, Kansas City, Mo., 
WHAZ, Troy, N. Y., WAAW, Omaha, 
Nebr., WPAH, Waupaca, Wis., KFKB, 
Milford, Kan., WSB, Atlanta, Ga., 
WOC, Davenport, Iowa, KSD, St. 
Louis, Mo., WTAS, Elgin, 111., WLW, 
Cincinnati, Ohio, WGR, Buffalo, N. Y., 
WRK, Hamilton, Ohio, WCBD, Zion, 
111., WBAV, Columbus, Ohio, WMC, 
Memphis, Tenn., WOS, Jefferson City, 
Mo., WDAR, Philadelphia, Pa., WOR, 
Newark, N. J., KFI, Los Angeles, Calif., 
WSZ, New York City, N. Y., WBAH, 
Minneapolis, Minn., KFKX, Hastings, 
Nebr., WOAW, Omaha, Nebr., WRC, 
Washington, D. C, CFCN, Calgary, 
Canada, KPO, San Francisco, Calif., 
8XJ, Cleveland, Ohio, KFDL, Denver, 
Colo. 

These stations total about 23,150 
miles and were logged between the hours 
of six p. m., and twelve-thirty a. m. 
Respectfully, 
WILSON B. LEMBERGER, 

2037 Osborn Street, Burlington, la. 



Now you will probably wonder why 
that deserves the title of DT. The 
secret that Wilson is only fourteen years 
old, and any youngster who will have 
patience to sit at a radio set for six hours 
to listen for DX ought to get the credit 
he should have. ATTA' BOY, Wilson! 




RADIO SCHOOL FOR WOMEN 
The first radio school for women has opened at the Bedford Y. M. C. A., 
Brooklyn, New York. It is the first school of its kind. Photo shows J. S. 
Peterson, the instructor, explaining the intricacies of the vacuum tube to 
his pupils. 



And while we have been gloating over 



tube records, we have probably been 
mentally reproached for not giving some 
thought to the crystal bugs, but don't 
convict us that way. Here's a kink for 
the crystal bugs that will no doubt 
receive the welcome and grateful thanks 
of many fans who are not so fortunate 
as to possess a tube set: 

RADIO AGE, 
Gentlemen : 

Yours of January 28 received ; in reply 
will say that the purpose of my previous 
letter was to have you publish this 
crystal innovation as a follow up on your 
eliminator. There is really nothing that 
I have done to improve on your idea, as I 
only stuck in a crystal detector and phone 
jack and ran the wires right through to 
the phones. Since writing my previous 
letter I have been fortunate enough to 
get DX on this hookup. 

Monday night I heard a speech at 
KDKA, East Pittsburgh, Pa., and 
incidentally, might mention that a friend 
to whom I gave this hookup got WWJ 
of Detroit, Mich., on it. It is a very 
sensitive hookup and works very fine 
with the crystal and you still can use 
it as a wave trap for your tube set if 
you happen to have one. 

I realize what a trial the people have 
when WJAZ or one of the other local 
stations of Chicago starts operating and 
I think there are a good many fans who 
are looking for a good efficient crystal 
hookup, and this is it. 

I am not much on drawing, but will 



do the best I can, so I enclose herewith 
a sketch of the idea. 

Yours very truly, 
H. A. ENGLEBAUGH, 

1328 Winona Street, Chicago, 111. 

P. S. I have used both No. 24 and 
22 DCC for the eight turns but they 
work about the same. — |H. A. E. 

Eureka! Perhaps this is what thou- 
sands of fans who can only afford a 
crystal set are looking for. To Mr. 
Englebaugh the entire credit goes — we 
never dreamed that the eliminator could 
be used that way. The eliminator was 
described in the January 1924 issue of 
RADIO AGE as an interference pre- 
venter, and since then, we have received 
fifty-seven different varieties of uses for the 
unit. The whole secret lies in the way you 
construct the unit; if you make it care- 
lessly and use poorly designed parts : 
you can't possibly expect results, and 
any fans who try out this unusual use 
of the eliminator should bear this in 
mind. Mr. Englebaugh would be pleafed 
to hear from fans who construct this 
trick receiver. A diagram of the whole 
smear is shown in Figure 1. 



Reflex fans probably will find the 
following letter of interest. 
RADIO AGE, 
Gentlemen: 

While looking through the Pickups 
page, I have been tempted to write the 
results I have obtained from my home- 
made Erla 3 tube Reflex. I use an indoor 
aerial strung between two rooms, and 



30 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



the following is a partial list of the sta- 
tions I have succeeded in hearing clearly 
and loudly. This does not mean I had 
to nearly bust an eardrum to listen. 
Those with the mark were heard on 
the loud speaker, which is a Morrison 
Phonograph Unit attached to a Clear 
Tone horn. 

KDKA, KYW, PWX, WAAN, 
WAAT, WBAN, WCAE, WCAL, 
WACM, WCAP, WCBD, WDAF, 
VVADP, WDAR, WEAF, WFAA, 
WFAB, WFI, WGR, WGY, WHAS, 
WHAZ, WHN, WIP, WJAX, WJAZ, 
WJY, WJZ, WLAG, WOAG, WOAP, 
WOC, WOR, WOS, WBAM, WSDX, 
WOAZ, WRC, WRW, WSAI, WSB, 
WTAM, WTAS, CHYC. Local stations 
not mentioned but have all been heard. 

I have not seen any reflex circuit 
featured with a list like this one, and 
would like to hear what the other reflex 
fans say. 

Yours tor radio, 

G. S. BAIRD, 

32 Maltbie Avenue, Suffern, N. Y. 

That's a nice little list, isn't it? You've 
got to give credit to Mr. Baird — we 
know how hard it is to make a reflex 
do its darndest. You fellows who are 
having trouble might give Mr. Baird a 
ring — perhaps he can give you some 
valuable suggestions. 



RADIO AGE, 
Gentlemen : 

It seems as if the Reinartz bugs have 
been falling behind of late with their 
reports, so thought I'd boost it a bit. 
About one month ago, I built a set for a 
friend of mine who had never operated 
a set and had only listened a few times. 
The first time I tuned in with the set I 
heard Havana, Cuba, Los Angeles, 
Calif., San Francisco, Calif., and Port- 
land, Ore., together with Calgary, Canada, 
and New York City. It was by far the 
loudest set I'd ever heard. Announce- 
ments and music from Kansas City and 
Omaha came in so loud that it could be 
heard across the room. We had no loud- 
speaker, but we hung the phones on the 
wall and still heard the signals. Later 
one stage of audio frequency amplifica- 
tion was added. The set was delivered 
Christmas eve and to date his record 
is as follows: WKAQ, KGW, KPO, 
PWX, KFI, KHJ, CFCN, CFCA, 
KFAF, KFKX, WAAW, WOAW, 
KFKB, WNAD, WFAA, WBAP, WOAI, 
WPAM, WOQ, WDAF, WHB, WOS, 
KSD, WOC, WEQU, WLAG, WBAH, 
KYW, WJAZ, WMAQ, WDAP, WTAS, 
WCBD, WMC, WHAS, WSY, WLW, 
WSAI, WTAM, WJAX, WCX, WWJ, 
WCAE, KDKA, WOO, WGR, WGY, 
WEAF, WOR, WCAP and WSB. 

Not a large list, only fifty-one stations, 
but pretty good for a newcomer. Wonder 
if any Kopprasch or Cockaday, "fiends" 
can report as good. The hookup is a 
slight modification of the standard 
Reinartz using two taps in the grid 
circuit and none in the plate or antenna. 
Other than these slight changes it is 
standard. 

Very truly yours, 

FRANK W. SMITH, 

.2306 Edward Street, St. Joseph, Mp, 



Good work, Mr. Smith. The reason 
your friend gets such good results is due 
to the fact that when you omitted the 
taps on the coils you unconsciously cut 
down many losses, and lowered the entire 
resistance of the circuit. We'll bet that 
the tuner is a peach for selectivity, too. 
It is a far wiser plan to make your coils 
of sufficient size to suit the wave desired 
and to use a sufficiently large condenser 
than it is to use a tapped coil and a 
smaller condenser. The losses incurred 
in the taps and dead ends of the coils, 
while not of appreciable notice in signal 
strength, will when removed increase 
the general effectiveness of the set as a 
whole. 




FRENCH GENIUS 

Latest portrait of General Gustave 
Ferrie, the man who has developed 
radio in France during and since 
the war. He is head of all the mili- 
tary radio stations in France. He 
controls the Eiffel Tower post as well 
as many other stations. 



Here's a letter from the town where 
RADIO AGE is printed: 

RADIO AGE, 
Gentlemen: 

This is to let you know that I have 
with the little "First Tube Set" and a 
one-stage amplifier pulled down through 
my antenna almost every station of 
importance from New York City to San 
Francisco, Calif. Here is a partial list 
of them: KDKA, KFAF, KFFZ, KFI, 
KHJ, KLZ, KPO, KYW, WEAF, 
WCAE, WCAP, WCBD, WCX, WWJ, 
WDAP, WEAH, WEAS, WGY, WHA, 
WHAN, WHB, WIAB, WIAO, WJAZ, 
WLAG, WHAS, WLW, WMAI, 
WMC, WOAG, WPAB, WPAC, WPAD, 
WSB, WSY, WTAM, WTAS and many 



others which 1 failed to put down when 
I heard them. 

It might be of interest to you that I 
have made five of these little receivers, 
and they always worked the first time I 
hook them in. 

Yours very trulv, 
MAX M. BARNHIZER, 

Mount Morris, 111. 

The little "first tube set" mentioned, 
above was described in detail in the 
October, 1923, issue of RADIO AGE,, 
and we have been getting lists that look 
like the call book on it ever since. 
RADIO AGE has a staunch bunch of 
boosters out in Mount Morris, who are 
employed in the plant where RADIO 
AGE is printed. Among them are H. V. 
Biery, Grover Hammet, W. I. Prugh 
and many others. And believe me, Mt. 
Morris is certainly radio nuts. They've 
got a fifty-piece brass band that broad- 
casts from WOC every once in awhile, 
and telephone interference and every- 
thing. Hot town, that. 



Here's a little letter which will make 
some of the fellows with super-hetero- 
dynes look like they have a glass arm: 
RADIO AGE, 
Gentlemen: 

Why all this fuss? There is no use 
talking, the Reinartz is by far the best 
receiver! (Ha! How do you like that 
DT's?— The Ed.) 

Come on, you Reinartz fellows — they 
aren't going to pull the wool over our 
EARS. This one ought to help testify 
to that. Here is a list of stations heard 
in two and one-half hours time: WWJ 
WSB, KSD, WCAE, CKCK, WHb' 
WFI, WLAP, WGY, KDKA, WSAI* 
WHN, WFAN, KHJ, WMAW WJz' 
WBAP, WCX, WOAW, WBAV.'wCAl' 
WJAN, WLW, WDAP, KFKB, and in 
addition to these mentioned I hear 
PWX, Havana, Cuba, Portland, Ore.,. 
Calgary, Can., San Diego, Calif., Saw 
Francisco and lots of others. 

Only a Reinartz will do this. They've 
got to show me. 

Yours very truly, 

H. J. BOYENGA, 

Greene, la. 

And that's that! All we're going to do 
now is to brace ourselves for the flock 
of letters which will come in in answei 
to this one telling Mr. Boyenga where 
to get off. It looks like he started some- 
thing. That's a good list — only two and 
a half hour's listening and twenty-five 
stations; you know some of these fellows 
think that they've nailed a record when 
they pull in twenty-five in a week. 



The following ought to be of interest 
to Lloyd E. Foltz, a fan who for the past 
several issues has been the target of 
much "razzing." Also to the users of 
Cockaday sets. 

RADIO AGE, 

Gentlemen: 

If you can spare the room in your 
Pickups section of the most valuable 
radio periodical published (Thank You 
— The Ed.) please print the following 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



31 



and I'll try and help Lloyd E. Foltz de- 
fend the "Cockaday DX title. 

The following stations were heard on a 
Type C Baldwin Loud Speaker with 
two stage of audio, the circuit, of course, 
being a Cockaday. All were heard loud 
and clear with enough volume to fill a 
good-sized bungalow! 

WLAQ, 360; WTAM, 390; WWJ, 
517; WJAZ, 448; WGI, 360; WGR, 
319; WEAF, 492; Wcap, 469; WSD, 
546; PWX, 400; WRC, 469; WOC, 484; 
VVCAE, 462; WSB, 429; WFAM, 360; 
WHN, 360; WCK, 360; WJAR, 360; 
CFCA, WSY, 360; WIAD, 360; KDKA, 
326; WOI, 360 (this station has a radius 
of only 200 miles); WPAH, 360; WFAA, 
476; WOS, 441; WCAL, 360; WOAI, 
385; WJAX, 390; WSAI, 309; KYW, 536; 
WLW, 309; WMAK, 360; WHA, 360; 
WCAE, 462; WJAD, 360; WOAN, 360; 
and KFKX, 286. 

You will notice that WOI of Ames, 
Iowa, has a radius of only 200 miles, but 
in spite of this fact I have heard them 
both clearly and loudly. I gave the meter 
wave length of the different stations for 
the reason that some of the fans don't 
seem to think that this circuit is capable 
of going from the lowest to the highest 
waves. I think that the foregoing will 
most clearly demonstrate this point. 
There is only ten meters difference be- 
tween my local station WHAS and 
WTAM, Cleveland, Ohio, and I have 
repeatedly listened to an entire concert 
from WTAM while Louisville was going 
full blast. 

Only five meters between WHAS and 
WOR at Newark, N. J., and 1 have also 



heard an entire concert from WOR, while 
Louisville was on with no interference 
from Louisville whatever. 

Any RADIO AGE reader desiring 
information on this set may get same 
gratis by writing me at Crestwood, Ky. 
I want to see the Cockaday bunch at the 
top. 

Here's hoping that I have contributed 
at least two or three good points for the 
Cockaday and a good many more for 
the RADIO AGE. 

Very truly yours, 

J. H. JONES, 
Crestwood, Ky. 

The Cockaday fans will probably 
welcome that letter, Mr. Jones, and will 
especially feel that it bears weight when 
we tell them that Mr. Jones is an old 
friend of RADIO AGE, and has been 
visiting the Pickups section before. 
It seems that Mr. Jones has at various 
times been a Reinartz fan, an Erla bug 
but this is the second letter we have 
had from him with reference to the 
Cockaday. 



RADIO AGE, 

Gentlemen: 

Purchased my first copy of RADIO 
AGE, January, 1924, and am much 
interested in the Pickups page. I would 
like to give you a slant at my list heard 
on a two-variometer single circuit set 
with detector only. The following are 
the stations heard since August, 1923. 
The amateur are all phone. If the list 
is too long, cut out the ones closer than 
500 miles. 

PWX, at Havana, Cuba, was tuned in 




at about 7:30 one evening through 
powerful interference created by WDAP. 

I have heard KFI and KHJ several 
times, one time when my antenna lead, 
in was lying on the roof. 

I use a UV 199 tube, 22 1-2 volts on 
the plate and an aerial of one wire about 
ninety feet long, including lead in. 
Have tuned in as many as twenty-eight 
stations in one evening, with KFI the 
farthest. I am leaving out several 
amateur stations which I have heard but 
in spite of that, my list totals 103 stations. 
I am enclosing a copy of my hookup, 
which I think will be of interest to fans. 
(We are showing the hookup in Figure 
2.) The list is as follows: KYW, 
WDAP, WMAQ, WPAD, WAAF, WTAS, 
WCBD, WOAW, WLW, KDKA, WMC, 
WLAG, WGY, WDAF, WSB, WHB, 
WSAI, WGR, WHAS, WWJ, WOC, 
WCAE, WFAA, WBAP, WBAV, WJAX, 
WDAR, WOO, WOS, WHAZ, WJY, 
KSD, WIAS, WCX, KFJK, WOR, 
WTAM, KOP, WBAH, WEAF, WCAP, 
KFDY, WIP, WHA, WEAH, WCK, 
WMAK, KFKB, WMAY, WSY, WAA, 
WHAM, CFAC, CFCN, CKCE, WRC, 
WPAH, PWX, 9CE, WRAD, WWAE, 
KFJL, KFKX, WEAS, WMAH, KLZ, 
KHJ, WBZ, WNAV, CKCK, KFDL, 
KFI, WIAO, 5LJ, 2BXL, 9DNI, 9BRX, 
9BRN, 9CNN, 9ASH, 9GB, 9JC, 9CJX, 
WCAL, KFIX, WABT, WEAN. 
Yours very truly, 

FRANCIS TYE. 

607 N. Eighth Avenue, Maywood, 111. 

Next time you send ijn a list, tear out 
the broadcast stations pages from some 
old RADIO AGE, and with a pencil 
indicate "leave this and this out, I've 
heard all the others." HI! That's a 
nice list, and will probably show the 
fellows who contemplate building the 
Rosenbloom circuit what it can do. 



Photo 
radio eq 
services. 



HISTORIC BROADCAST 
shows John Hammond in crypt below Bethlehem Chapel operating 
uipment by which the nation heard Ex-President Wilson's funeral 



RADIO AGE, 
Gentlemen: 

Have been trying several hookups but 
have not had much success and as I 
had the parts I thought I would try your 
first tube set as described in the January 
issue of RADIO AGE. Got it wired up 
at about 8:45 p. m., and up to 10:30 
p. m., I got the following twelve stations 
which I think is some good work for 
one and three-quarters hours. I am 
using a C 299 tube and they all come 
like a house afire. It sure is some hook- 
up. Stations were received as I am 
listing them: WCAE, WCBD, KDKA, 
WOAW, OMAHA, WPAH, WLW, 
WHB, WHAZ, WDAR, WGR, KFKF, 
and KFKB. 

Would recommend the circuit to any- 
one having trouble with their sets, as 
this one sure gives the satisfaction. 
Yours truly, 

A. W. NORTH, 
61 N. Lincoln Avenue, Fond du Lac, Wis. 

Now this is the part that gets us; 
a fellow will monkey around, mortgage 
his house and sell his car to get money 
enough for a ten tube super-heterodyne — 
and then when he can't get it to work 
goes and tries out a circuit of the type 
mentioned. By jimminy, it's not the 
kind of circuit that counts, it's the make 
of the set. The secret of that little 
"First Tube" circuit lies in the fact that 



32 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



it has so lew parts that you can't help 
hut construct it with few losses. On the 
other hand, when you improve on a 
circuit, add taps, more condensers and 
more fancy coils you usually increase 
the resistance and losses in the circuit 
and the result is a bum set. If you take 
our advice, make a simple little tuner, 
learn how to keep the losses down 
and enjoy a variety of stations that 
you couldn't get with a poorly built 
ten tube super-heterodyne. Frankly, 
we say from personal experience in the 
game that if you find that an amateur 
takes more than two hours to wire up 
and make a circuit it really calls for an 
investigation. The general rule is to 
slam the thing together and then give 
it a test, and when it doesn't work — 
classify it as a failure. That's the thing 
that won't jibe with a large receiver, 
and it really takes weeks and often 
months before you get all the parts 
working in proper unison, because there 
are so many of them. With the little 
"First Tube" circuit the whole thing is 
based upon a few major pieces of appa- 
ratus, and it is almost impossible to fail 
with it. We don't mean to reflect on 
Mr. North's former sets or anything 
like that — we just feel that his letter is 
typical of many ill advised fans, who 
think that the only way you can get 
DX is to add more tubes, power and 
spend more money on a larger set, 
when the real solution of their problem 
lies in reconstructing their original set 
with the intention of cutting out losses 
when they do so. 



Well, fellows, I guess that's about 
enough for this issue. True to our word, 
we've been running them pretty freely, 
and rather than crowd out some good 
feature, we'd better quit. 

Before we do so the Pickups Editor 
wants to extend his thanks to the fans 
who sent in their letters but whose 
letters are not published, due to lack of 
space. 

By the way, it looks like the Editor 
has been putting his two cents here and 
there, and I suppose he has read them 
pretty thoroughly. 

S'long! See you next month. 



fhip-£hore Record 

All records were broken for commercial 
600 meter continuous wave transmis- 
sion when Operator M. A. Obradovic, of 
i he S. S. "West Nilus," while ninety- 
Cue miles north of Wellington, New 
Zealand, copied a number of messages 
direct from WIM, the Radio 6«rpora- 
tion of America station at Chatham on 
the Massachusetts coast. The distance 
is 9,300 miles and perfect reception ob- 
tained in broad daylight. 

Operator M. A. Obradovic, whose re- 
ception has been checked and confirmed, 
sent a letter to marine superintendent 
at Chatham on December 23, in which he 
reported the history-making achieve- 
ment. The letter reached the United 
States more than fifty days after it was 
mailed in New Zealand. 



Washington Show 

Washington, D. C. — Washington's ra- 
dio dealers with the co-operation of of- 
ficials of the federal government will 
stage in Convention Hall here the week 
of March 19 to 26, one of the most pre- 
tentious radio expositions ever held in the 
United States. 

With the array of exhibits that have 
featured radio shows in other cities, aug- 
mented by special government displays, 
some of which have never been on public 
view, Washington's first radio show is 
destined to attract nation-wide attention. 

The Department of Commerce which 
has supervision and control over all of 
America's activities in the field of radio; 
the Bureau of Standards, the govern- 
ment's famous experimental laboratory, 
and other federal agencies interested 
directly or indirectly with radio and its 
development, will take an active and 
leading part in making the radio expo- 
sition in the nation's capital an epoch in 
radio history. 

The fighting arm of the government — 
the army, navy and marine corps — also 
will be represented at the show with ex- 
hibits of historical value. The navy has 
planned to exhibit a replica of the 300 
watt radio transmitting station on the 
giant dirigible, "Shenandoah," which 
kept the navy department in constant 
communication with the big ship during 
her sensational gale-driven flight up the 
Atlantic coast in January. The army, 
which proudly boasts that its radio en- 
gineers are at least two years in advance 
of the radio wizards employed by the 
leading manufacturers of radio prod- 
ucts in the development of improved 
apparatus, has promised an exhibit to 
prove its claim. 

Officials of the government depart- 
ments, including President Coolidge, the 
chief executive, and members of his cab- 
inet, are expected to take an important 
part in the elaborate and unique enter- 
tainment features of the show, tentative 
arrangements for which already have been 
made. 



Radio in the Movies 

A praiseworthy bit of co-operation 
with the radio industry has just been re- 
leased by Kinograms news weekly in the 
shape of "Behind the Scenes of a Broad- 
casting Station." 

E. F. McDonald, Jr., of the Zenith- 
Edgewater Beach Hotel Broadcasting 
Station, WJAZ, and Ray L. Hall, head of 
the Kinograms news weekly chanced to 
meet one day on the stage of Selwyn 
theatre in New York. 

"Radio speaking, I am rather well ac- 
quainted with WJAZ," said Mr. Hall. 

"It has often entertained me in my 
home in New York state. I have never 
seen the staticn, however. Often won- 
dered what it looked like." 

Said Mr. McDonald, "I shall be glad 
to arrange that not only you see it, but 
all of your big family of Kinogram fans 
the country over." 

That was the starter of the film. 

Next to seeing the station with one's 
own eyes, the picture is the closest to a 
full realization of the beauty of the crys- 
tal studio; the complexities of the oper- 
ating and motor rooms; the gaiety of the 
guests in the marine dining room; the 
eager faces of the famous Oriole orchestra; 
and all that happens when the artist 
stands in front of the microphone and 
sings to his eight million or more WJAZ 
listeners. 

Movie audiences are introduced to the 
grand opera stars: Florence Macbeth, 
Angelo Minghetti, Virgilio Lazzari, Mary 
Fabian and Myrna Shadow of the Chi- 
cago Civic Opera Company in periodic 
flashes of the crystal studio. We are 
shown how the concert is put on the ether 
at the very moment it is being received 
in the different parts of the country; in a 
play spot of a metropolitan section in 
the east, vast throngs of skaters are en- 
tertained with the very same concert by 
means of the Zenith radio sets conven- 
iently placed in different parts of the 
lagoon. 



This Coupon Saves You Money 

Radio Age Annual, the best hookup book, and one year's subscription — 
$3. If you want this double bargain sign the coupon and mail at once. 
Send price by check, currency or money order. If by check add five cents 
for exchange. 

Radio Age, Inc., 

500 North Dearborn Street 

Chicago: 

Gentlemen: Please send me by return mai your illustrated Radio Age Annual, containing 
more than 100 big pages of hookups and instructions and also send me Radio Age, The Mag- 
azine of the Hour, for one year. I enclose $3. This will give me a one dollar book and a $2.50 

subscription at a saving of fifty cents. Please start my subscription with the _ 

number. 

Name _ 

Street address 

City ...._ 

State „ _ 

If book alone is desired, mark cross here [™] and enclose $1.00. If subscription only, 
mark cross here Q and enclose $2.50. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



M 




E. S. M., Detroit, Mich. 

Question: Your February issue came 
today, and first of all I must compliment 
you on its contents and general appear- 
ance. I am a reader of several radio 
publications, but this RADIO AGE 
takes the cake. It's a King Bee — don't 
let it slip. Now I have a little kick 
coming. I want to know why the 
author of that code article didn't give us 
more code Q signals while he was at it. 
I got interested in the stuff and have 
been talking it to the wife ever since, 
till she's nearly dazy. Let's have some 
more Q signals as soon as possible. 

Answer: I am printing elsewhere in 
this department a complete list of Q 
signals as are used by the transmitting 
operators in the course of the regular 
wireless conversations. I might add 
that now, due to the fact that internation- 
al amateur communication is becoming 
more and more common, the various 
nations are adopting a form of calling 
which will enable listeners to identify 
foreign amateur stations. Thus an 
American amateur calling a French 
"ham" would call F8AB F8AB F8AB 
U9DQS U9DQS U9DQS, etc. The F 
would classify him as French and the U 
QERttL 

A/FUTRODV/UE (IF 



preceding the American call identifies 
the last station as United States. The 
same applies to Canadian who sign 
"C," the British "G," and Australian 
"A." Sometimes the Australian sign 
"Aussie" and then their call. For full 
details on this code work, those interested 
should see the November and December 
issues of RADIO AGE, and to keep 
pace with amateur code developments, 
it is advised that readers refer to the 
amateur code journal QST at Hartford, 
Connecticut, a periodical which special- 
izes in advanced amateur transmitting 
and receiving problems. 



J. W. H., Topeka, Kans. 

Question: I want to thank you for 
your January article in the RADIO 
AGE on the Junior Heterodyne. That is 
an article a great many have been looking 
for, particularly us fellows that are in 
the game with a shoe string and an oat 
meal can. Beg pardon if I pull a boner, 
but is not your tickler circuit short 
circuted on socket VI plate post? Having 
recently built a 5-tube Neutrodyne, 
using ice cream containers to build the 
transformers on, I would like to record 
the result for your information and 



TRANSFORMERS 



advice. The transformers are whed 15 
turns on primary with 60 turns on 
secondary, tapped at 15th turn for 
neutrodons. Am using Bremler-Tully 
.0005 MF vernier variable condensers, 
19 plates on rotor and 2 on vernier. 
The result is that all balancing is done on 
the to 55 divisions of the condenser 
dials, which are 100 division dials. 
Cannot separate stations on this space 
to good advantage. St. Louis balances 
on 55 55 55 and Cincinnati on 8 8 8 
degree settings on the dials. Hastings, 
Nebr., KFKX comes in on about half 
of the three verniers, that is a 286 meter 
station. There are a good many stations 
down around the wave that Hastings 
operates on, and I would like to bring 
them in. My friends have made trans- 
formers 13 and 54, 14 and 56, and mine 
is 15 and 60 windings. They advise me 
to cut plates off of these condensers in 
order to spread the range over 100 divi- 
sions of my dials. The scrap is heated at 
times, as I cannot see it that way. It 
seems to me that I should not destroy 
the condenser capacity. Now I don't 
want to bind you down with a lot of red 
tape and ask you to sign on the dotted 
line. I know that each technical engineer 



00035 MP 



FIXED COUPLER 



GROUND 




6RIDLEM J'3 MEGOHMS 
6 RID CONDENSER ■ 0OO2S MF 

FWED .OOlMF 



^#M#I»I« 

4&>T /6-30Y 



Lw 




I 



d) 4=' 



WVAMW 



-=HMM|ih 

6g-9dv 



R 



Figure 1. A hookup diagram of a three tube neutrodyne. The transformers are made according to the Instruc- 
tions outlined in the accompanying answer. The fixed coupler is constructed according to the directions given in 
the October, 1923, RADIO AGE, and consists of eight turns of No. 28 DCC wire on a three and one-quarter inch tube. 
The secondary consists of fifty turns of the same size wire wound on the same tube, with a separation of about one 
inch between the windings. No taps are taken off the fixed coupler. The condensers across the secondaries of the 
Neutrodyne transformers are 17 plates. 



34 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



INTERNATIONAL RADIOTELEGRAPHIC CONVENTION 

List of Abbreviations to Be Used in Radio Com- 
munication 



Abbre- 
viation 



PRB 



ORA 
ORB 
ORC 
QRD 
QRF 
ORG 
ORH 
QRJ 
QRK 
ORL 



QRM 
ORN 

QRO 

ORP 
ORO 
ORS 
ORT 
ORU 
ORV 
ORW 

ORX 
ORY 
ORZ 
OSA 

OSB 
OSC 
OSD 

OSF 

OSG 

OSH 

OSJ 

QSK 

QSL 

OSM 

OSN 

OSO 

OSP 

oso 

OSR 
QST 
QSU 

*QSV 

QSW 
OSX 
OSV 

osz 

OTA 
OTC 
OTE 

OTF 



Question 



Do you wish to communicate by 
means of the International Signal 
Code? 

What ship or coast station is that? 

What is your distance? 

What is your true bearing? 

Where are you bound for?.__ 

Where are you bound from? 

What line do you belong to? 

What is your wave length in meters? 

How many words have you to send?.. 

How do you receive me? 

Are you receiving badly? Shall I send 
20? 



for adjustment? 

Are you being Interfered with?.. 
Are the atmospherics strong? ._ 

Shall I increase power? 

Shall I decrease power? 

Shall I send faster? 

Shall I send slower? 

Shall I stop sending? 



Are you ready? 

Are you busy? 



Shall I stand by? 

When will be my turn? 

Are my signals weak? 

Are my signals strong?.— 

I Is my tone bad? 

\ Is my spark bad? 

Is my spacing bad? 

What is your time? 

Is transmission to be in alternate or- 
der or in series? 



What rate shall I collect for? 

Is the last radiogram cancelled?..... 

Did you get my receipt? 

What is your true course?.. 

Are you in communication with 
land? 

Are you in communication with any 
ship or station (or: with )? 

Shall I inform that you are 

calling him? 

Is calling me? 

Will you forward the radiogram? 

Have you received the general call?.... 

Please call me when you have fin- 
ished (or: at o'clock)? 

Is public correspondence being han- 
dled? 

Shall I increase my spark frequency? 

Shall I decrease my spark frequency? 

Shall I send on a wave length of..._ 

meters? 



Have you anything to transmit? 

What Is my true bearing? 



What Is my position?.. 



Answer or Notice 

I wish to communicate by means of the 
International Signal Code. 

This is 

My distance is 

My true bearing is degrees. 

I am bound for 

I am bound from 

I belong to the Line. 

My wave length is meters. 

I have words to send. 

I am receiving well. 

I am receiving badly. Please send 20. 



for adjustment. 
I am being interfered with. 
Atmospherics are very strong. 
Increase power. 
Decrease power. 
Send faster. 
Send slower. 
Stop sending. 
I have nothing for you. 
I am ready. All right now. 

I am busy (or: I am busy with ). 

Please do not Interfere. 
Stand by. I will call you when required. 

Your turn will be No 

Your signals are weak. 
Your signals are strong. 
The tone is bad. 
The spark is bad. 
Your spacing Is bad. 

My time is 

Transmission will be in alternate order. 

Transmission will be in series of 5 mes- 
sages. 

Transmission will be In series of 10 mes- 
sages. 

Collect 

The last radiogram is cancelled. 

Please acknowledge. 

My true course is degrees. 

I am not in communication with land. 



I am In communication with 

(through ) 

Inform that I am calling him. 



You are being called by 

I will forward the radiogram. 
General call to all stations. 
Will call when I have finished. 

Public correspondence is being handled. 

Please do not Interfere. 
Increase your spark frequency. 
Decrease your spark frequency 
Let us change to the wave length of... 

meters. 
Send each word twice. I have difficulty 

in receiving you. 
Repeat the last radiogram. 
I have something to transmit. 
Your true bearing is degrees 

from 

Your position is latitude _ 

longitude. 



*Public correspondence Is any radio work, official or private, handled on commercial 
wave lengths. 

When an abbreviation is followed by a mark of Interrogation, it refers to the question 
Indicated for that abbreviation. 



has his own special ratio for these trans- 
formers. I am disposed to make new- 
transformers in hopes that my set will be 
bettei, and would appreciate a few words 
from you with regard to ratios. 

Answer: First of all I want to tell you 
that as far as beginners in the radio 
game are concerned, I am not in favor of 
recommending neutrodyne receivers to 
novices — the balancing of the tubes 
requires quite a knowledge of radio 
principles and tube characteristics, and 
inasmuch as no two tubes are exactly 
the same with respect to capacity, 
it is a pietty hard thing for the novice to 
balance a neutrodyne receiver properly. 
Of the many neutrodynes I have seen in 
possession of broadcast listeners, I find 



that very few of the fellows know enough 
about them to get the best results. 
However, with respect to your trans- 
formers, the general rule is to wind the 
ratios of these coils about 4 to 1. This is 
greatly dependent upon the type of 
tube used, and for UV 201 A, WD 11 and 
UV 199, I would recommend a ratio of 
primary on a 3-inch (diameter) tube 
wound with about 15 turns of No. 26 
DCC wire, and the secondary on a 3 1-2- 
inch (diameter) tube wound with 50 
turns of No. 26 DCC. This ratio is a 
matter of experiment, and the results 
obtained are a matter of the type of tube 
used. Also hand wound coils vary a 
great deal, and no definite number can 
be given, outside of this general specifica- 



tion. A tap at the 15th turn of the 
secondary for the connection of the 
neutrodon is recommended. Often this 
is not necessary, the neutrodon being 
connected directly to one side of the 
parallel circuit as shown in Figure 1. 
The condenser across the secondary 
should be a 17 plate. When the tap is 
added, the connections are made as in 
Figure 2. For those interested in Neu- 
trodyne circuits we would say that 
the most advantageous method of ad- 
justing the neutrodon is to proceed in 
the following manner. It is assumed 
that two stages of neutrodyne radio 
frequency amplification are used. First, 
place a piece of cardboard in the tube 
socket of the first radio frequency stage 
so that the tube does not make contact 
with any of the connectors of the tube 
socket. Light the second tube and de- 
tector (if an amplifiei is used do not use 
it; or closer adjustments may be obtained 
with the detector alone.) Select some 
strong local station, and if no station is in 
your immediate vicinity, set up a tem- 
porary wavemeter as a source of oscilla- 
tions using a small buzzer as the source 
of your power. Here is where the deli- 
cate adjustment lies. Vary the capacity 
of the neutrodon of the first radio fre- 
quency amplifier tube until no signal is 
heard whatever from either the station or 
wavemeter, whichever you may be using. 
Keep the wavemeter at a distance of 
about six feet from the set. If the signal 
fails to disappeai, try a larger neutrodon. 
A good one may be constructed according 
to instructions printed in January, 1924, 
RADIO AGE. The neutrodon must be 
absolutely correctly adjusted or the set 
will give only indifferent results. When 
the first stage has been properly balanced, 
proceed in the same manner with the 
second stage. During this adjustment 
the first stage of radio frequency should 
be on. Don't make these adjustments in 
a haphazard manner — if you do the set 
won't work properly. It will only get 
local stations, will howl and give poor 
results. The adjustment of the neutro- 
dons together with the careful con- 
struction of the set is the secret of the 
Neutrodyne circuit. The trouble with J. 
W. H.'s receiver is quite apparent. The 
condensers and coils which he is using are 
too large for the 300 meter stations. 
In any case where it is desired to lower 
the wave length of a circuit, it is advis- 
able to decrease both the capacity and 
inductance of the circuit respectively. 
In your case would recommend that you 
wind your transformers according to the 
ratios mentioned, and decrease the size 
of your condenser. This would enable 
you to tune with the entire condenser, 
making use of the whole dial scale of 
degrees. The additional 45 degrees 
that you mention as now inactive are 
not in use and are only dead timber, 
only serving to make the tuning of the 
receiver more critical. 



C. T. S., Warren, Pa. 

Question: I have built the Haynes 
circuit using the 180 degree variocoupler 
as shown in your hookup published in the 
December RADIO AGE, but find that in 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



35 




QJMetOKM 




iWilWlit- 



A6AT 3-22 '/*v. 8-€>9-9ov. 

Figure 2. Another diagram of the Neutrodyne, with taps taken off the transformers as described in the accom 
panying question showing how the connections are made when this method of connecting the compensation con- 
densers is used. 



order to tune in, the position of the rotor 
is very critical, and the tube spills over all 
too easily. I am using No. 18 wire on 
the stator and No. 20 on the rotor 
with a 23 plate condenser and with a 
UV 199 tube. It seems that the 23 plate 
condenser works better than the 11 plate 
in the circuit. Would like to have you 
answer the following questions on the 
above circuit. Would you advise using 
No. 20 wire on the stator or taking off 
some of the No. 18 wire to make the cir- 
cuit balance more easily? Is the Haynes 
considered a single circuit? Is it as selec- 
tive as the Cockaday circuit? Can the 
variocoupler be purchased complete? 
What is the diameter of the rotor and 
stator? Please furnish hookup for this 
circuit using push-pull amplification with 
UV 199 tubes. Will I have as loud a 
reception with push-pull transformers as 
I get with the 10:1 and 3:1 transformers? 
Answer: Would not advise that you 
disturb the winding of the stator coil, 
as this probably is not at fault. You 
might rewind the rotor with some of the 
No. 18 wire, and experiment a little with 
the exact number of turns. The action 
you describe suggests too large a tickler 
coil, and it would probably be a wise 
thing to cut down on the number of turns. 
It also might be attributed to too high a 
plate voltage on the detector bulb. 
With the U. V 199's, a plate voltage of 
anywhere from 18 to 45 volts is often 
possible and necessary in the matter of 
getting the best results out of the circuit. 
Increase the size of your grid leak, and 
the circuit will not be so finicky. The 
Haynes is a modified single circuit, but 
because it has two permutations for 
tuning it would probably be better to 
classify it as a two circuit tuner. If 
properly operated and constructed it is 
about equal with the Cockaday for selec- 
tivity. This however is dependent upon 
the operator, and careful handling is the 
only way it can be brought to comparison 
with the Cockaday. Ordinarily, the 
Cockaday is considered super-selective. 
The variocoupler can be purchased from 
the Haynes-Grimn Co., of New York. 



but in any case if the diameter of the 
stator exceeds 3 3-4 inches, the number 
of turns on both coils should be decreased. 
The amplifier described in the January 
issue of RADIO AGE, being a push-pull 
circuit is connected up by placing the 
input of the first push-pull transformer 
to the output (phone connections) of the 
detector. Your reception will be louder 
and clearer due to the fact that your 
tubes are only working half the time, and 
higher plate voltage can be applied. 



working antenna, the whole thing being 
a sort of a lead in without a flat top giving 
a strong sharp signal as described by Mr. 
Pearne in the February issue in his articel 
on antenna analogy. 



H. L. C, Joliet, 111. 

Question: I would like to ask a ques- 
tion concerning my receiver on which I 
am having trouble with an alternating 
current hum. My antenna is close to a 
power line and three big transformers. 
Would another wire alongside of my 
present antenna grounded at both ends 
reduce the hum? What would you 
suggest? 

Answer : The grounded wire you speak 
of would only detract from the effective- 
ness of your receiver, and lower the 
effective height of your antenna as a 
whole. If you can't run your antenna at 
right angles to the source of the inter- 
feience, would advise that you erect a 
pole of as high an altitude as you can, 
and run the aerial up and down (vertic- 
ally) in the air. The effectiveness of your 
set would increase materially, and it 
would also be at right angles to all the 
wires which tun parallel to the earth. 



J. F. M., Chicago, 111. 

Question: Will you kindly give me a 
sketch showing how we can both get 
results without interfeiing with one 
another on the following tangle: My 
four wire antenna was up about 2 years 
and a party moved in down stairs and 
put one wire over mine and the result is 
that I cannot get outside stations. 

Answer: The same goes for you JFM ; 
run your antenna straight up and down 
in the ait on a single pole as high as you 



F. M. H., San Diego, Cal. 

Question: We are troubled very great- 
ly with interference from a powerful arc 
station (call being NPL) here around 
San Diego, and I would appreciate it if 
you would inform me as to whether it 
would be advisable to use a wave trap 
with the little "First Tube" receiver in 
this locality. This station makes life 
miserable around here for radio fans, 
and if this little set described in your 
article cannot tune out any of this inter- 
ference it would be practically useless. 
What would you advise? 

Answer: We have read with consider- 
able concern of the powerful arc inter- 
ference created by NPL, and understand 
that the San Diego Radio Club has 
created a movement to put a stop to the 
"mush" created by the interfering arc 
of this station. With reference to the 
circuit you mention, we wish to say that 
if it is carefully constructed of good 
apparatus it will tune about as closely 
as any two circuit set devised. While 
not over selective, it will give admirable 
results where interference is not too 
strong. If the interference you speak of 
is particularly violent, we would certainly 
recommend the addition of a wave filter 
as described in January, 1924, and would 
recommend that you use a 43 plate con- 
denser instead of a 23 plate to cover the 
wave of NPL inasmuch as we know that 
they transmit on a higher wave than the 
broadcasting stations. We want to be 
frank with you and say this in defense 
of the receiver. Arc interference is com- 
posed of so called "harmonics" which occur 
at various waves with varying intensity. 
If one of these harmonics of any consid- 
erable audibility happens to be on the 
wave you desire to listen on, no set can 
tune them out. It is entirely a matter of 
how frequent these harmonics are, and 



can affoid. Your antenna will still be at 
completely made up. The diameter of the right angles to your friend's, and you where they occur that will judge whether 
rotor and stator are not very important, have the advantage of moie effective you will be able to shut them out 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 




SUNSET STATION 

Above is the studio of the New General Electric broadcasting station, KGO, at Oakland, Calif. At the right is a 
glimpse of the antennae. Below is the station building and the operating room. The portraits are those of Martin 
P. Rice, director of broadcasting for the General Electric Company at Oakland, Denver and Schenectady, and J. 
A. Cranston, Pacific coast manager of the General Electric Co. 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



37 



WMat the Broadcasters 

are Doing 





KFKX, The Repeating Broadcasting Station 

By D. G. Little and F. Falknor, Radio Engineers, Westinghouse Electric and Manufacturing Company 

From the Electrical Journal, January, 1924 



ON NOVEMBER 22, 1923, there 
was put into operation the latest 
type of radio broadcasting sta- 
tion — a type which presages a great ad- 
vance in the art of broadcasting radio 
programs. The repeating of programs 
which are originally presented in Pitts- 
burgh, makes available to more distant 
listeners the high quality of program 
which is obtainable only in the larger 
cities. While experiments along this 
line have been carried on for some time, 
KFKX is the first station to seriously 
attempt a service of relaying or repeat- 
ing regularly a previously announced 
radio program, broadcast from a dis- 
tant station. 

It has long been desirable to inter- 
connect broadcasting stations in various 
parts of the country, so that national 
events could be enjoyed by the nation 
as a whole instead of by only those in a 
small area. At least two solutions of 
the problem are to-day in use to some 
extent. One is the use of long-distance 
telephone lines and the other the use of 
a primary broadcasting wave or fre- 
quency. This primary frequency must 
necessarily be selected in a band where 
atmospherics and existing radio stations 
interfere the least. It is also highly 
desirable to have this carrier frequency 
more independent of intensity fluctua- 
tions due to change from daylight to 
darkness than generally is the case in 
the series of frequencies now used for 
broadcasting. From an interference 
standpoint, frequencies at least as high 
as 3,000 kilocycles are obviously the best. 
The high frequencies have many ad- 
vantages for such purposes. One of 
the most important of these is that 
"fading," which is so annoying at the 
usual frequencies, is reduced at the 
higher frequency to the point where its 
effects are negligible. The elimination 
of fading is one of the first essentials of 
successful repeating by radio. The 
3,200 kilocycle waves seem to carry 
almost, if not quite, as well during the 
daytime as at night, thus meeting an- 
other requirement of successful repeat- 
ing. High-frequency transmission is 
also exceptionally free from static inter- 



ference. While special equipment is 
necessary both for the transmitting and 
receiving of programs at this high fre- 
quency, there is no particular difficulty 
involved in designing equipment which 
will give the highest type of service. 
Not an Experiment 

While the first of this type to establish 
regular service, Station KFKX is by 
no means an experimental station. The 
repeating of programs at high frequency 
from Station KDKA has been carried 
on in an experimental manner by the 
Westinghouse Company for some time. 

In June, 1922, it was decided to con- 
duct preliminary tests on a large scale 
by repeating, at Cleveland, Ohio, signals 
transmitted from East Pittsburgh, Pa. 
Station KDKA was equipped to trans- 





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Station KYW, Chicago, broadcasts 
news bulletins at half-hour intervals 
throughout the day and night. Paul 
C. Kahn, 3222 Carroll Ave., Chicago, 
has invented an alarm clock device 
that automatically "brings in" the 
station. The clock is timed with the 
station time and the alarm is set 
for the half hour. When the alarm 
sounds the lever attached to the 
alarm wind comes down and com- 
pletes the circuit. When the an- 
nouncer signs off the clock is again 
set for the next period. 



mit at frequencies near 3",000 kilocycles 
while the Cleveland station's equipment 
consisted of a receiver for this frequency, 
and an 803 kilocycle transmitter. This 
apparatus was completely installed and 
ready for actual tests about September 
1. Tests conducted between these two 
points, from September, 1922, until 
January, 1923, indicated that the use 
of a very high frequency as a primary 
carrier in a repeating system was not 
only highly desirable but entirely pos- 
sible from a practical standpoint. 

In July, 1923, it was decided to at- 
tempt repeating over a greater distance, 
with the object of transmitting the pro- 
grams of KDKA to the Pacific coast. 
A series of tests was made between 
KDKA at East Pittsburgh and points 
intermediate between St. Louis, Mo. 
and Denver, Colo., to determine the 
maximum distance from KDKA that 
the secondary transmitter could be 
located. After the completion of this 
investigation, it was decided that the 
point in question was roughly near the 
center of the boundary line between 
Nebraska and Kansas. 

Near Center of United States 

The locating of a city or town having 
the desired facilities for power and suit- 
able space available was next necessary. 
The city of Hastings, Nebraska, seemed 
to meet all necessary requirements, 
and arrangements were made to locate 
the equipment at that place. Hastings 
is located almost ideally for the purpose 
of repeating programs from Pittsburgh 
so that they may be heard with ordinary 
receiving equipment throughout all the 
middle west and can be heard on the 
Pacific coast with less elaborate equip- 
ment than is necessary to receive directly 
from KDKA. 

The new station is very close to the 
center of the United States. The country 
around Hastings is level and the par- 
ticular location is relatively free from 
static and other radio interferences. 
The nearest broadcasting station of 500 
watts or more is at Omaha, Nebr., a 
distance of 142 miles. Hastings is al- 
most 1,000 miles from Pittsburgh and 
1,200 miles from Los Angeles. Under 



38 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 




CANADIANS IN CONFERENCE 
Recent session of prominent radio men and officials of the Department of Commerce at which 450 meter wave 
length for ship and shore communication was discussed and suggestions made for an allotment for another wave 
length. Photo shows Canadian radio men who were present at the conference. Left to right — C. P. Edwards, di- 
rector of department of Marine and Fisheries; W. A. Rusch, Supt. of Canadian Government Radio service; J. H. 
Thompson and H. M. Short, general manager of the Marconi Wireless Telegraph Company of Canada. 



ordinary conditions its programs should 
be heard at any point west of Pittsburgh. 
The opening program was received on 
loud speakers at Washington, D. C, 
about 1,100 miles and New York City, 
over 1,200 miles from Hastings. 

Although designed primarily for re- 
peating programs from KDKA, a com- 
plete studio is provided at Hastings 
where local programs will be given at 
regular intervals. The first program on 
the night of November 22, was given 
partly from Hastings and partly from 
East Pittsburgh. The principal address 
delivered in the studio at East Pittsburgh 
was received with loud speakers at a 
convention in session at Salt Lake City, 
Utah, 700 miles distant from Hastings 
and 1,700 miles from Pittsburgh. Re- 
ports from this convention and from 
other western points, as well as from 
New York and Washington, indicate 
that this first program was heard clearly 
over a wide range of territory. 

When a program from East Pittsburgh 
is to be repeated at Hastings, KDKA 
transmits on its regular frequency of 
920 kilocycles (326 meters) and at the 
same time sends out the same program 
on a carrier frequency of 3,200 kilocycles 
(94 meters). The 3,200 kilocycle wave 
is picked up at Hastings and the output 
from this receiver is used to control the 
radio transmitter at Hastings. In this 
manner programs from East Pittsburgh 
are rebroadcast with practically no time 
lag from KFXX at a frequency of 1,050 
kilocycles (286 meters). Provision is 
also made at Hastings for repeating the 
signals at a second high frequency to a 
third more distant repeating station, 
when this becomes desirable. 

Local Interference 

The initial step, after Hastings had 
been selected as the location of the new 
station, was the installation of experi- 
mental equipment for both receiving 
and broadcasting. The problem of re- 
broadcasting or radio-repeating was then 
undertaken. As most of the major 
problems had already been worked out 
at Cleveland, the difficulties to be over- 
come at Hastings were mostly of a detail 
nature. 



The most troublesome and perplexing 
of all details soon proved to be that of 
local interference caused by leaky power 
lines and the operation of electrothera- 
peutic apparatus by physicians and 
hospitals. Most of this equipment is 
based on resonant circuit principle and, 
because of the high decrement and over- 
abundance of harmonics generally found, 
causes a constant band of interference 
from about 300 to at least 3,750 kilo- 
cycles. By experiment it was found 
that in the case of some of the above 
mentioned apparatus the radius of this 
area of interference was at least a half 
mile. Since it was impossible to remove 
this interference, the receiving equip- 
ment used to pick up the Pittsburgh 
signal was moved out of the city and 
placed about one mile north of the local 
transmitter. 

In the new receiving location, it was 
found that the received speech level 
was satisfactory for repeating at all 
times except between 8 a. m. and 4 p. m. 
central standard time. Various primary 
carrier wave frequencies between 3,448 
and 3,000 kilocycles were used in order 
to determine the most suitable one. 
Above 3,333 kilocycles it was found 
that the signal was maximum about 
7 p. m., central standard time, and would 
fall to about ten per cent strength be- 
fore 8 p. m. At 3,000 kilocycles the 
signal strength increased until about 
1 1 p. m. and then remained approxi- 
mately constant until about 4 a. m. 
From this data one would naturally 
assume that at some frequency between 
these two hours the strength of signal 
should remain constant at all hours. 
In fact, it so happened in all cases ob- 
served that slightly above 3,333 kilo- 
cycles the signal was relatively weak at 
all times although it apparently main- 
tained a constant level from at least 
4 p. m. to 9 p. m. 

All of these effects on signal strength 
were also observed in Cleveland, Ohio, 
during January, 1923. No opportunity 
to corroborate the Cleveland observa- 
tions was afforded, however, until the 
establishing of the Hastings station. 
It is of interest to note that the two sets 



of observations were taken after ten 
month's lapse of tima, at different periods 
of the year, and with entirely different 
receiving and transmitting equipment. 
Since the most of the repeating was to 
take place in the evening, a frequency 
was selected near 3,200 kilocycles. 

Antenna 

The antenna is of cage construction, 
there being two cages of eight No. 12 
copper wires each, on 1.5 inch diameter 
spacers. The cage length is 35 feet. 
These are swung tightly between ten 
foot cross arms at the tops of two fifty- 
four foot wooden poles, as shown in 
Fig. 6. The down lead is a 1.5 inch 
diameter copper tube rigidly supported 
on porcelain insulators from one of the 
poles. The antenna ammeter and addi- 
tional loading inductances are connected 
in series with the down lead part way 
up the pole. An insulated counterpoise 
is supported on stakes a short distance 
from the ground and there is also an 
experimental counterpoise similar in 
construction to the antenna between 
the lower cross arms and the poles. 

Stulio 

In addition to the repeating apparatus 
installed at Hastings, a local studio is 
also provided in the business section of 
Hastings. The room used is about fifteen 
by twenty feet. The floor and walls of 
this room are suitably padded to reduce 
sound reflection to a minimum. A com- 
plete condenser microphone system has 
been installed and used exclusively. 
A novel feature of this studio equipment 
is that "back to back" amplifiers are 
used entirely. The studio and station, 
separated nearly one mile, are connected 
by several telephone circuits, over which 
orders are sent to and from the studio 
and the program speech sent to the 
station. 

Cost is Low 

Tests that have been conducted up 
to the present time show that while 
constructional difficulties naturally in- 
crease at these high frequencies, the 
results obtained are most encouraging. 
The costs of construction, maintenance, 



RADIO AGE— "THE MAGAZINE OP THE HOUR" 



39 



and operation of a high-frequency sys- 
tem of radio repeating is far below that 
of wire lines. The performance is also 
infinitely better from the standpoint of 
distortion of the audio signal trans- 
mitted. Contrary to the condition on 
wire lines, the speech frequencies suffer 
the same attenuation throughout the 
limits of audibility, thereby greatly im- 
proving the quality of transmission. 
There are two apparent advantages to 
wire transmission, in that the number 
of channels open to use has practically 
no limit, and that attenuation is con- 
stant at all times of day. In answer to 
the first advantage it may be said that 
assuming 3,000 cycles per second as the 
necessary wave band for radio use, 1,000 
channels are available between 6,000 
and 3,000 kilocycles. This is ample for 
the needs of this continent. Tests also 
show that it is possible to use carrier 
frequencies having satisfactory char- 
acteristics for daylight use. 



Phonograph Stations 

WABU, the new Victor talking ma- 
chine broadcasting station at Camden, 
N. J., will soon give the public an oppor- 
tunity to hear phonograph records in 
the making. That is, radio fans will be 
permitted to hear original records before 
they are released. When famous vocal- 
ists or musicians are about to perform for 
the reproduction on master phonograph 
records in the studio, a microphone will 
be placed alongside the recording appar- 
atus and as the artist renders his piece for 
record the radio fans will hear it over the air. 

The Columbia Graphophone Company, 
through co-operation of the A. T. & T. 
Company and station WEAF, will also 
start broadcasting new records soon. 

This system is likened to "first nights" 
at operas and theatrical productions, 
seats at which are always sold at a pre- 
mium or distributed to the elite and mem- 
bers of the press. By means of radio 
broadcasting, fans will now be permitted 
to hear new records before they are put 
on the market. It is a unique feature, 
welcomed by all receiver owners who await 
the advent with pleasant anticipation. 



Schools Use Radio 

For the first time in the history of 
education active use of radio broadcast- 
ing on an extensive and permanent basis 
as an educational aid was inaugurated 
on February 18, when the Board of Edu- 
cation of the city of New York, acting with 
the co-operation of the Radio Corporation 
of America, broadcast through station 
WJZ the first of the daily educational radio 
programs which have been scheduled. 

These programs, arranged by the 
newly created radio committee of the 
Board of Education, are broadcast from 
2 to 2:30 o'clock on every school day. 
A special and permanent broadcasting 
apparatus is to be installed in the office 
of Dr. William L. Ettinger, superintend- 
ent of schools, and the programs on every 
Tuesday afternoon will be broadcast by 
WJZ directly from there. On all other 
school days the programs will be given 
at the studio of station WJZ at Broadcast 
Central, Aeolian building. 

The programs are designed primarily to 




SON OF GREAT COMPOSER 
Siegfried Wagner, son of the great German composer, Richard Wagner, 
speaking from Station WJZ, when thousands of radio listeners heard his 
appeal for $200,000 which will enable him to resume the musical festivals 
at Bayreuth, which were originated by his father. 



acquaint the people with the work of the 
schools, educate the public as to education. 



More Stations 

The limits of "Radio Land" are being 



sometimes confused with American ama- 
teur stations, which also start with the 
district numbers. 

With the licensing of KFNG, at Cold- 
water, Miss., on January 18, every 
state in the union had one or more broad- 
casters, it was learned at the Bureau of 
Navigation, Department of Commerce. 



extended so rapidly on both land and sea, 
and so many fans are asking for aid in 
identifying stations outside our borders, 
we are listing hereafter the neighboring Tnis is not tne fi rst time, however, that 
foreign broadcasting stations. eacn state has been listed; last year a 

In Canada, for example, there are now broadcasting station opened up in Cor 



thirty-six stations broadcasting, many of 
which are heard in the states. They all 
are identified by their initial call letter 
"C," assigned to the dominion by the 
International Bureau at Berne. 

Cuba has thirty-one stations which 
broadcast, eighteen of them situated in 
Havana. Except for well-known PWX, 
these stations all have initial numbers 
instead of letters, and are in consequence 



inth, Miss., which completed the roster, 
but this station later dropped out, 
leaving one of the forty-eight states un- 
represented. 

During January, twenty-seven new 
broadcasting stations started operation 
and twenty signed off for the last time, the 
Department of Commerce states. Broad- 
casting gained seven stations, and on 
February 1, stood at 554 stations. 



40 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



WITH 




Summer Business 

The danger of permitting radio to 
become a seasonal business is pointed out 
in a recent speech by David Sarnoff, vice- 
president and general manager of the 
Radio Corporation. Since the radio com- 
bine has more at stake than any other 
individual or [collective interest, Mr. 
Sarnoff's advice should carry weight. 
He said: 

"I think one of the dangers to the radio 
manufacturer at this time, and of course 
ultimately to the distributor, is the 
thought which is in the mind of a great 
many distributors, apparently, that radio 
is a desirable thing because it offers an 
opportunity for sales during a period of 
the year when other lines of merchan- 
dise do not move readily, and I think 
that the distributor and the dealer to- 
day, more than any one else, are making 
radio a seasonable business. There is 
not the slightest excuse, in my opinion, 



for having a seasonable business in radio. 
It has been amply demonstrated that 
people will use radio in the summer, when 
you give them sets at the right prices, in 
the right way and with the proper con- 
venience. 

"What are the dangers of a seasonable 
business? The season only lasts a few 
months, and it takes two or three months 
to get up steam. You are losing mo- 
mentum as you are going downhill, and 
you have a valley in the curve when you 
are doing nothing, and you force new 
patterns, new designs, because you want 
to start off at the beginning of the sea- 
son with a new line of merchandise. 
When you find yourself at the end of the 
season with an old line of merchandise 
you want to give it away to get rid of it. 
You don't want it on the shelves. That 
is true of the cloak and suit business. 
If you get rnto that kind of business, 
however, neither the manufacturer nor 




the distributor is going to be happy. The 
manufacturer has got to keep his factory 
running all the year, round. He has to 
have quantity production, so as to re- 
duce prices. He has to carry on con- 
sistent and insistent national advertising. 
He has to have an inventory and the like. 

"Therefore, unless there is a very good 
natural reason over which you have no 
control, for creating a seasonable busi- 
ness — you can't sell overcoats in the sum- 
mer — I say you are heading for trouble 
if you do create such business merely be- 
cause it happens to fit in with your situ- 
ation at the time. You must avoid that 
in every way possible." 



Distortionless Amplifier 

Continuing their work of improve- 
ment of radio station WBZ in Springfield, 
Westinghouse engineers are putting in 
the latest devices and apparatus devel- 
oped for better broadcasting of all types. 
The most recent addition to the excel- 
lent equipment of this New England 
station is a voice amplifier of entirely 
new design which reproduces and mag- 
nifies the sound impulses without dis- 
tortion before they are "fed" to the sta- 
tion's transmitter. 



Radio Exports Grow 

Radio exports for the year 1923, 
totaled $3,448,112, compared with $2,- 
897,799 last year, according; to Depart- 
ment of Commerce statistics. While 
the shipments of radio apparatus form 
only about five per cent of the total 
value of all electrical exports, which in 
1923 passed the $72,000,000 mark, radio 
exports increased about seven per cent 
out of a total gain of $9,000,000. De- 
cember radio exports totaled $335,308, 
compared with $381,827 for November 
and $270,061 in October. 



NEW "LONG-45" 
Another new circuit has appeared in the radio field. Using but one tube, 
it works on a loop aerial. It is really a new type of regenerative circuit con- 
struction, using a special type variable inductance and other parts. 



Cockaday Coil 

The Precision Coil Company, Inc., 
is the exclusive manufacturer of the 
Authorized Cockaday Coil. It is author- 
ized by him and each coil bears the word 
"approved" above his signature. It is 
wound on hard rubber tubes (one eighth 
inch wall) with No. 18 double silk covered 
magnet wire. All terminals have copper 
soldering tabs and are located to give 
shortest leads possible to the condensers. 
Nickeled fittings give the coil a finished 
appearance. There is no shellac, paint 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



41 



=3£= 



=><= 



=3l= 



=5£= 



=?€= 



=5«= 



=5£= 



=>£= 




Your Radio Problems Solved 
for 30 Cents in Stamps 



I 



F YOU are constructing a receiving set, and you need help in the way of clear 
diagrams and full detailed descriptions you may have it by return mail. 

We have laid aside a limited number of back numbers of Radio Age for you. Be- 
low we are listing the hook-ups and circuit diagrams to be found in these magazines. 
Select the ones you want, enclose 30 cents in stamps for each one desired. 

We advise immediate attention to this as the stock of back numbers of several 
issues already has been exhausted. 



May, 1922 

— -How to make a simple Crystal Set for $6. 

June, 1922 

■ — How to make a Receiving Transformer. 
— Aerials under ground and under water. 
— Electric light wires as auxiliary to radio. 

October, 1922 

—How to make a Tube Unit for $23 to $37. 
— How to make an Audio Frequency Amplifying Trans- 
former. 

November, 1922 

— Photo-electric Detector Tubes. 

— Design of a portable short-wave radio wavemeter. 

January, 1923 

— How to make a sharp-tuning Crystal Detector. 
— Fixed condensers in home-made receiving sets. 
— Description of loading coil for simple sets. 

May, 1923 

— How to make the Erla single-tube reflex receiver. 
— How to make a portable Reinartz set for summer use. 



June, 1923 

— -How to build the new Kaufman receiver. 
— -What about your antenna? 



July, 1923 

— The Grimes inverse duplex system. 
— How to read and follow symbols. 
■ — Proper antenna for tuning. 



September, 1923 

— How to load your set to receive new wave lengths. 
— -Simple Radio Frequency Receiver. 



October, 1923 

— Your First Tube Set. 



November, 1923 

— The Super-Heterodyne. 
■ — A Three-Circuit Tuner. 
— How to Learn Code. 



December, 1923 

— -Building the Haynes Receiver. 

— -Combined Amplifier and Loud Speaker. 

— A selective Crystal Receiver. 



January, 1924 

— Tuning Out Interference — -Wave Traps — Elimina- 
tors — -Filters. 

The article which was favored with the frrateful interest of the radio 
public after its announcement by Station W.IAZ. 

— A Junior Super-Heterodyne. 
— Push-Pull Amplifier. 
— Rosenbloom Circuit. 



February, 1924 

— How to make a battery charger. 

— Improved Reinartz Circuit. 

■ — Interference rejectors 

— Single Tube Heterodyne. 

— How antenna functions. 

— Adding two audio stages to selective receiver which 

began as a crystal set. 
—Superdyne receiver. 



RADIO AGE, Inc. 

500-510 North Dearborn Street ------- 



CHICAGO, ILL. 




42 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



or varnish on the coil. The manufacturer 
claims for it: High dielectric strength, 
low moisture absorption, maximum sensi- 
tivity, minimum capacity effect, low 
leakage, high selectivity. The price is 
$5.50. 



The Teledyne 

A new four-tube radio receiving set, 
to be known as the Teledyne and em- 
ploying engineering features which over- 
come radiation, generally credited as 
the worst form of radio "interference," 
is announced by Bowden Washington, 
chief engineer of the Cutting & Wash- 
ington Radio Corporation. 

The receiver, according to Washington, 
has the following advantages over the 
conventional double circuit set: 

!. Will not transmit. 

2. Increased volume. 

3. Greatly increased range. 

4. Somewhat increased selectivity over 
the best conventional double circuit 
sets. 

"It has for some time been evident 
that the customary 'transmitting' re- 
generative set was becoming a grave 
menace to the future of radio and yet 
this principle which so greatly increases 
volume and range could not be dis- 
carded," said Washington. 

"Experiments made in view of over- 
coming this problem of radiation led to 
the perfection of the Teledyne, a set 
which takes advantage of this previously 
known method in the radio art of secur- 
ing volume, range and selectivity but 
does not throw wave impulses into the 
air and annoy neighboring sets. 

"The first stage of the Teledyne cir- 
cuit operates in the following manner: 

"It is well-known that when a resonant 
circuit, consisting of an inductance and a 
capacity in parallel is placed in series 
with the plate circuit of a vacuum tube, 
the grid circuit of which is also resonated 
to the same frequency, the resonant 
plate circuit will produce oscillations 
and somewhat off this resonant point, 
'negative resistance' or regeneration. 
If this circuit is coupled with the plate 
circuit with sufficiently close coupling 




the same phenomena will occur. If, 
however, the coupling is at a certain 
critical value regeneration can be pro- 
duced without possibility of oscillation. 
This latter value is that used in the 
Teledyne. 

"The antenna circuit consists of the 
usual inductance but of two values, 
tuned by a series condenser, which, by 
the way, operates a cam switch choosing 
either of these inductance values over 
the two available 180 degree scales, with 
the grid-filament input leads across this 
inductance. 

"The plate circuit of the first stage 
is coupled, at the critical value mentioned 
heretofore to the grid inductance of the 
detector, which latter is tuned by the 
usual variable condenser. The adjust- 
ment of this condenser resonates the 
detector grid circuit and at the same 
time regenerates the radio-frequency 
amplifier, thereby increasing its response 
by lowering the antenna resistance. 

"The antenna inductance which is 
also the grid inductance of the radio- 
frequency amplifier is carefully mounted 
at minimum coupling position with the 
detector grid inductance. This is neces- 
sary in order to prevent parasitic feed 
back causing oscillation of the first tube 
and, incidentally, as the detector is the 
only tube which can be over regenerated 
and oscillate, this minimum coupling 
position prevents these oscillations from 
getting into the antenna circuit. 

"The tuning of this set is extremely 
simple and either of two methods may 
be employed. First, the regeneration 
of the detector may be left low and the 
antenna condenser and detector grid 
circuit tuning condenser may be handled 
in a manner resembling the tuning of 



.a one-stage neutrodyne. The second' 
method is similar to the usual manner 
of handling a two circuit regenerative; 
receiver i. e., oscillate the detector, turn; 
its condenser until a heterodyne note 
appears, tune the antenna until it is^ 
loudest and reduce the regeneration. 
The difference is that the heterodyne 
note does not go out on the air and be- 
come a pest for several blocks in all 
directions. 

"Owing to the double use of regenera- 
tion this receiver with four tubes is more 
sensitive than the conventional five- 
tube neutrodyne. 

"It is of course extremely simple with 
the neutrodyne to tune a station once 
logged, as it is with this set, but it is 
somewhat more difficult to pick up new 
stations. Hunting for new stations 
with the Teledyne is as simple as with 
the old-fashioned single circuit receiver 
but without its drawbacks. 



Crosley Lowers Prices 

The Crosley Radio Corporation an- 
nounces that greatly increased produc- 
tion makes possible the reduction of 
prices on the various complete sets 
manufactured by the big Cincinnati 
company. The Crosley Company makes 
more receivers than any other organiza- 
tion in the world and its announcement 
will be of general interest to the trade and 
to .the radio public. 

A new two-tube receiver is offered con- 
sisting of Armstrong regenerative detec- 
tor and one stage of audio frequency 
amplification, giving loud speaker volume 
on local stations at all times and on 
distant stations under fair receiving con- 
ditions. The instrument, known as the 
Crosley Model 51, sells at $18.50. 

Reductions on other Crosley sets are 
as follows: Type V, single tube regenera- 
tive, reduced from $20 to $16; two stage 
audio frequency amplifier to match the 
Type V, reduced from $20 to $18; Model 
VI, two tube receiver, reduced from*$30 
to $24; Type 3-B, three-tube Armstrong 
regenerative in mahogany cabinet, re- 
duced from $50 to $42; Model X-J, four- 
tube receiver, reduced from $65 to $55; 
Type 3-C, three-tube Armstrong con- 
solette model, with built-in loud speaker, 
reduced from $125 
to $H0: Model 
X-L, four-tube set, 
reduced from $140 
to $120. 




+ 22^8 



TELEDYNE DIAGRAM 
Wiring diagram of the Teledyne, four-tube receiver which Cutting & Washington offer with the announcement 
that it will not transmit and that it has good range, volume and selectivity. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



43 



Hongkong Listens In 

The urge to broadcast and listen in 
has reached Hongkong, China, where a 
few foreigners interested in radio got 
together about eight months ago and 
formed the Hongkong Radio Society, 
membership in which now numbers over 
a hundred, Consul Webber reports to 
the Department of Commerce. Today 
there are over 500 listeners in but it is 
estimated that this number will be 
doubled within a year's time. 

So far there are only two broadcasting 
stations in Hongkong, the consul states; 
one, a 100-watt American set, operated by 
the local telephone company which 
transmits phonograph music for an hour 
each evening; the other, a ten-watt 
Canadian set is operated by the Radio 
Communication Company, Ltd. 



WLAG Record 

Minneapolis, Minn. — Another Ameri- 
can radio broadcasting record was re- 
corded when a letter was received by 
the Cutting & Washington station, 
WLAG, from Mrs. Charlotte Jorgenson, 
Kragero, Norway, saying that the writer 
and her husband had been listening 
regularly to WLAG concerts. 

The letter, addressed to Mrs. A. H. 
Dieseth, Minneapolis, a neighbor of 
Mrs. Jorgenson when the latter lived 
in Minneapolis, said Mrs. Jorgenson 
heard Hazel Dieseth, a daughter of Mrs. 
Dieseth, sing on a WLAG program and 
recognized her voice and name. 

It is approximately 5,176 miles from 
Minneapolis to Kragero, Norway. 



Radio exports for the year 1923 
totaled $3,448,112, compared with $2,- 
897,799 last year, according to Depart- 
ment of Commerce statistics. 

classified advertisements 



•nx c«ni» per word per insertion, 
«nd addreaa muat be counted. 



in advance. Name 
Each initial count* 

u on* word. Copy muil be received by the 15th •( 

eaonth for succeeding month's i**u*. 



HELP WANTED 



U. S. Government Positions. $100 to $250 month. 
Quick increase. Become Railway Mail Clerks — City 
Mail Carriers — Postoffice Clerks. Income Tax Auditors- 
Steady work. No strikes — no layoffs. Pleasant, in- 
teresting. Short hours. Paid vacation. Influence 
unnecessary. Schedule examination places — free. 
Men-women, 18 up. Write immediately. Franklin 
Institute, Dept. G, 114, Rochester, N. Y. 



FREE HOOKUP 



^ixty-thouaand mile* on Home-made Receiver. Twen- 
ty-six hundred mile range. Hundred-station log and 
Hookup free. Spencer Roach, 2905 Columbia Avenue, 
Philadelphia, Pa. 



BOOKS 



If you have not bought your Relnarta Book, fully 
illustrated with hook-up* and clear description of 
how to make this popular circuit, send 32.50 In money 
•rder ,r currency and wa will send you the booklet "Reln- 
srta Radio" and place you on the subscription list of 
Radio Age for on* year. Address Radio Age, S00 N 
Dearborn Street. Chicago, III. 

RADIO CALL CARDS printed TO ORDER. Red call, 
black printing. 100, $1.75; 200, $2.75, prepaid. Color 
changes 35c extra. Government postals lc extra each 
card. LETTERHEADS 8 1-2x5 1-2 AND ENVELOPES, 
100 EACH, $2.25; 200 EACH, $3.25. ARRL emblem used 
on cards or stationery if requested. Send TODAY. 
De partment 62C, Radio Printers , Mendota, Illinois. 

RADIO ODDS AND ENDS 
No. 14 square tinned bus wire — 2 ft. lengths — 64 feet 
for $1.00. $1.20 set of 8 lettered binding posts— 60c. 
Spaghetti — 3 ft. lengths, red, yellow, green or black — 
7 lengths — 21 ft.— $1.00. 50 assorted brass screws, 
nuts, washers, lugs, etc. — -50c. All four items prepaid 
return mail — $3.00. Radio list for stamp — none free. 
Kladag Radio Laboratories, Kent, Ohio. 

FOR RENT Factory with wood working machinery 

and power installed, suitable for making Radio Cabi- 
nets. Also office and show room if desired. William 
H. Gardner, 7326 Roosevelt Road, Forest Park, III. 



Exit Variocoupler 

Enter Erla Selectoformer 





Superiorworth of Erla audio 
transformers, shown in their 
exclusive ability to amplify 
three stages without distor- 
tion, improves any set. $5 




Erla condensers alone carry 
a certificate of accuracy on 
their labels. Look for the 
words "Tested Capacity" 
when buying. 35c to 75c ea. 




Patented telescoping rim of 
Erla bezels fits any Y% " to 14* 
panel, neatly screeningopen- 
ings required for tube venti- 
>: ion. Nickel or enamel, 20c 




Reliable and clear reception 
is assured through the Erla 
fixed crystal rectifier, re- 
quiring no adjustment and 
lasting indefinitely. List $ I 



Combines Improved Properties of 
Coupler and Wavetrap 

Again Erla contributes notably to radio advance- 
ment. Erla Selectoformer, replacing alike vario- 
coupler and wavetrap, greatly increases volume 
and selectivity in radio receivers, at the same time 
reducing cost. 

Selectoformer, as the name implies, operates simul- 
taneously as a selector and radio frequency trans- 
former, picking off of the antenna the one wave- 
length desired and amplifyingit to normal strength. 
Thus is avoided the interference common to re- 
ceivers that depend for selectivity upon tuning 
the coarse antenna system. Also, because of the 
amplification brought to bear, there is eliminated 
the loss of energy encountered in wavetraps of 
conventional type. 

With Selectoformer, distant signals come in loud 
and clear, even with powerful local broadcasting 
in progress. Tone quality, likewise, is greatly im- 
proved, through reduction of static and other 
disturbances. 

Control of the Selectoformer is effected through the 
23-plate condenser already built into most receiv- 
ing units. Installation is a matter of moments only. 
For complete details regarding this and other Erla 
improvements, including latest reflex circuits, ask 
your dealer for Erla Bulletin No. 20, distributed 
gratis; or write, giving your dealer's name. 

Electrical Research Laboratories 

Dept. M 2515 Michigan Ave., Chicago 

£ r?£A 



The Little Wonder 

Tho smallest, yet 
most efficient Trans- 
former ever made. 
Maximum reproduc- 
tion volume, mini- 
mum dis to r t i o n, 
100% shielded. 

PREMIER 

"HEGEHOG" 
i Cfl '/ 2 Arlual Size Trade Mark 

>*° AUDIO TRANSFORMER 

Mounts anywhere — save space in assembly. We guar- 
antee it unconditionally. Try them in your next 
■■hook up." Ratio 1 to 3, 1 to 4. 1 to 5. $3.50; 
1 to 10, $4.50. Ask your dealer. Write for bulle- 
tin No. 02. which describes in detail the full line of 
ritEMIElt quality Radio Parts. 

pmnipr fotirti fcompimy 

3803 Ravenswnod Ave. Chicago 







=TEN IN 0NE!= 

Ten issues of Radio Age, up to and 
including the April, 1923, number, 
have been bound in heavy cloth. 
One of these fine volumes will be 
sent postpaid to any address with 
one year's subscription to Radio 
Age for the special price of $3.50. 
The book has many hook-ups 
and articles you may have missed. 
Send money order or check to 

RADIO AGE, INC., 

500 N. Dearborn St., Chicago, III. 

"Let our Hook-ups Be Your Guide" 



44 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



Acme Charger 

The Acme battery charger for radio 
A and B, also automobile batteries has 
recently been brought out on the market. 
The capacities that these battery chargers 
are built in are two ampere and five 
imperc- sizes with an attachment on 
both sizes to charge up to and including 
36 B type cells 

The construction and design is unique, 
and the operating characteristics art- 
such that Radio A batteries can be 
charged while set is in operation. 

These battery chargers are being manu- 
factured by The Acme Electric and 
Manufacturing Company, Cleveland, 
Ohio. 

Selectoformer 

The need of variocouplers, switches, 
taps, etc., is largely done away with by 
the Selectoformer just designed by the 
Electrical Research Laboratories of Chi- 
cago. The manufacturers announce 
that it permits of greater selectivity in 
practically any tuning unit now using a 
variocoupler, except in one-tube reflex 
sets. It requires no adjustment and has 
for its main object the coupling of the 
antenna to the receiver without causing 
a broadening of signals. 

The antenna circuit is never tuned to 
resonance with any particular incoming 
signal and coupling of signal to the 
receiver is only sufficient to excite the 
receiver at the wave length to which 
it is tuned, without adding the resistance 
of the antenna circuit to the secondary 
circuit, which always causes a broadening 
and loss of signals. 



With the usual variocoupler it is 
possible to reduce the inductive coupling 
between the primary and the secondary 
to a very low value, but capacitive coup- 
ling exists which allows as full a coupling 
as if the total inductive coupling were 
maximum. The inductive and capacitive 
coupling between the primary and sec- 
ondary circuits is always fixed at a very- 
low value by the selectoformer. With 
other fixed couplers, reducing the coup- 
ling reduces the volume of signals. 



condenser and when so used it actually 
adds to the strength of the incoming 
signals. It also prevents reradiation 
from regenerative sets, or others which 
oscillate, when it is used as an absorbing 
circuit for such oscillations. 




If your newsdealer has sold out 
his supply of Radio Age you are 
likely to miss just the hook-up that 
you haye been looking for. To 
avoid any such chance fill out the 
coupon in this issue and send in you 
subscription. Then you will be safe. 
And don't forget that with each 
subscription at the special price of 
$2.50 a year. We send you free the 
popular Reinartz Radio booklet 
FREE. Address Radio Age, 500 N. 
Dearborn Street, Chicago. III. 



The Selectoformer, due to its particular 
design, reduces the resistance of the 
secondary circuit and therefore increases 
the signal volume. 

The selectoformer increases the selec- 
tivity when substituted for a vario- 
coupler, or loose coupler, and is especially 
good in the two and three tube reflex- 
sets. 

It also makes an excellent wave trap 
when used with a 23-plate variable 



Radio Music Fund 

Clarence H. Mackay, Felix M. War- 
burg, Frederick A. Julliard and A. D. 
Wilt, Jr., announce that they have con- 
stituted themselves a committee to be 
known as the Radio Music Fund Com- 
mittee, with the object of raising a fund 
to be known as the Radio Music Fund for 
the purpose of broadcasting radio music 
concerts by the world's greatest artists. 

The committee has selected station 
WEAF, the broadcasting station of the 
American Telephone and Telegraph Com- 
pany, 195 Broadway, New York City, to 
broadcast the proposed concerts because 



c GOOD SOLDERING MEANS GOOD RECEPTION" 




The "Jiffy" Torch 

and 

Soldering Outfit 



anil 



The JIFFY self-blowing gasoline torch and 
soldering outfit is the only complete set on the 
market, which will withstand continued and hard 
usage over a long period of years. The torch 
cannot explode, and develops an extreme heat of 
2,300 degrees F. under prio-electric test. Simply 
touch a match to the burner and the torch op- 
erates. There are no needle valves or adjust- 
ments to get out of order, and no pump. 

The set consists of one JIFFY TORCH, copper soldering iron, bottle of non-corrosive flux, solder 

metal stand. Price, $2.00 postpaid anywhere in the U. S. or Canada. 

The JIFFY TORCH only packed in fibre box. Price, $1.25 postpaid. 

If your dealer can't supply you, send stamps, cash or money order or sent C. O. D. 

Handycap Manufacturing Corp. 

DEPT. A RIVERDALE, ILL. 

Dealers Inquiries Solicited 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



45 



of the well-known quality of transmission 
from this station. Concert Management 
Arthur Judson, manager of eminent 
artists and of the Philharmonic, Phila- 
delphia and the Cincinnati orchestras, 
will handle the engagement of artists for 
these concerts. 

The members of the committee, who 
are already well known for their activi- 
ties in support of things musical, believe 
that radio offers a wide and hitherto 
undeveloped field for stimulating the 
increasing public interest in good music. 
The committee hopes through the Radio 
Music Fund to afford to thousands of 
people, who for one reason or another 
are unable to be present at concerts and 
the opera, the opportunity of hearing by 
radio, the world's best musical talent. 

Prominent broadcasting stations have 
received hundreds of letters from the 
radio audience not only expressing 
appreciation of programs but offering 
to contribute financially toward the 
immense cost of maintaining programs. 
The Radio Music Fund Committee 
offers the organization through which 
the radio audience can contribute to the 
financial support of radio music programs. 
The committee has designated Central 
Union Trust Company of New York to 
act as depository of the fund. All con- 
tributions should be made payable to 
the Radio Music Fund and sent to Cen- 
tral Union Trust Company of New 
York, 80 Broadway, New York City, 
and should be accompanied by the 
name and address of the contributors. 
The depository will acknowledge receipt 
of contributions by postcards 

The committee invites contributions 
to the Radio Music Fund of from one 
dollar upwards. The fund will be held 
by Central Union Trust Company of 
New York subject to the order of the 
committee and will be expended undei 
the direction of the committee. If, 
in the opinion of the committee, the 
contributions received are not sufficient 
to warrant going ahead with the plan, 
the committee will notify the bank to 
that effect and all contributions will be 
returned as far as possible to the con- 
tributors. 

All funds contributed will be used for 
obtaining the service of artists and for 
direct expenses, and a financial state- 
ment will be published or sent to the 
contributors at the close of the season. 
If, after the presentation of radio 
concerts shall have begun, the committee 
shall deem it advisable to discontinue 
such concerts, any balance remaining 
in the Radio Music Fund may be return- 
ed to the contributors or disposed of for 
musical or educational purposes as may 
be determined by the committee. 

The expense of broadcasting will be 
borne by the American Telephone and 
Telegraph Company and aside from 
incidental expenses in connection with 
the administration of the fund, the entire 
contributions of the radio audience will 
be available for the maintenance of broad- 
casting programs. When contributions 
sufficient to warrant it are received, the 
committee will endeavor to engage the 
services of prominent artists to appear 




&a JT , 

IMF 




For AH 

Superheterodynes 

and 

Ultradynes 

Equity 10,000 Mile Meter R. F. Transformers 

Now the Superheterodyne and Ultradyne are advanced to the 
pinnacle of perfection! 100% efficiency is now possible through this 
very latest development — the Equity 10,000 Meter R. F. Trans- 
former — designed especially for the Superheterodyne and the Ul- 
tradyen. Entirely different! No transformer so efficient. 10,000 
Meter Wave Band Peak — assuring the very sharpest tuning. No 
steel or iron core to broaden your wave Band. The coils are honey 
comb wound with double green silk. Case, 3"x3"xl%", genuine 
moulded bakelite. Type R2 for all Superhetero- a» __ r*g\ 
dynes. Type Rl for first R. F. Transformer for «$> */ ,jU 

use in Ultradyne. Satisfaction guaranteed or M — 

money refunded. Either, each postpaid, • 

Complete Parts Carried in Stock For All the Standard Super- 
heterodyne Hookups at reasonable prices. Junior Superheterodyne, 
1 tube Heterodyne and Ultradyne Hookups 10c postpaid. 

Now Drill Panels Accurately 

"Church Universal Template" Locates Position for All Drill 
Holes. No Guesswork — No spoiled Panels. 





The greatest little aid for set builders yet invented. A marvel for effi- 
ciency. All holes now can be drilled in their accurate positions. No more 
Fussing — no more spoiled panels — no more crude workmanship — no more 
guesswork. Easily, quickly, accurately, finds position for all holes. Marks 
the holes on panels for instant drilling. A great time, trouble and labor 
saver. Satisfaction or money refunded. Postpaid $1.25. 

WRITE FOR FREE BULLETIN. (Dealer's Correspondence Invited.) 



17 NWABflSH /TVE. •»- . Dept. 201 ~-CHIC/IGO. 

Not the Cheapest — But the Best —Satisfaction or Money Back 



46 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



during the remainder of the present 
season which ends May 1. In the future, 
if the plan works out successfully, a more 
definite organization may be effected 
and the concert season extended over a 
longer period. 



Broadcasters inform RADIO AGE that 
it is the avowed intention of the Ameri- 
can Telephone and Telegraph Company 
to control broadcasting. It is sug- 
gested that one result of the fund 
plan, as described in the foregoing, 
would be to introduce the practice of 
paying performers who now are quite 
willing to entertain the radio millions 
without pay". It is pointed out that with 
such a fund the bigger companies might 
be able to pay their entertainers and 
thus make it very difficult for other 
broadcasters to obtain the services of 
artists without paying them. Thus the 
old plan to drive out the independent 
broadcaster by depriving him of his 
entertainment and make of broadcasting 
a virtual monopoly in the hands of the 
few would be furthered. 



Radio Writers Entertained by 
the Allen-Bradley Com- 
pany of Milwaukee 

THROUGH the courtesy of the 
Allen-Bradley Company of Mil- 
waukee, a few well known writers 
of radio articles were invited to inspect 
the factor)' where the Bradleystats and 
Bradleyleaks are manufactured and to 
attend the meeting of the American 
Radio Relay League, held in Milwaukee 
on February 14. The party, which was 
conducted to the Wisconsin city by 
Mr. Gohl, Chicago representative of the 
company, consisted of Mr. David Grimes, 
of the Sleeper Radio Corporation of 
New York, Mr. E. T. Flewelling, Mr. 
Harry J. Marx and Mr. Milo Gurney of 
the Radio Digest and Mr. Frank D. 
Pearne of Radio Age. Under the 
careful guidance of Mr. Gohl the party 
reached the factory without mishap 
and spent the entire afternoon inspecting 
the latest modern methods of manu- 
facturing. This factory is certainly a 
credit to Milwaukee. Everything used 
in the construction of their apparatus, 




with the exception of the porcelain units, 
are manufactured under one roof, even 
to the carbon discs used in the resistance 
units. Up-to-date testing methods and 
inspections assure one that the finished 
product is as perfect as human intelli- 
gence can make it. Mr. Harry Bradley 
personally conducted the party through 
the factory and explained in detail how 
everything, from the tiny Bradley 
switches to the gigantic power controllers, 
are constructed, after which he took the 
party to the Milwaukee Athletic Club 
for dinner. At the Club the party was 
joined by several members of the Allen- 
Bradley Company, Mr. Bruns of 
Radio Age and some of the members of 
the American Radio Relay League. 
After a splendid supper, the host, Mr. 
Bradley, finally got the party started 
for the A. R. R. L. meeting, where they 
arrived in time to find the hall so crowded 
that even standing room was at a pre- 
mium. This large attendance shows the 
interest which the A. R. R. L. members 
take in their meetings and speaks well 
for the future of radio. The meeting 
was turned over to the visito'rs, who 
talked on many subjects pertaining to 
radio. Mr. Marx gave the first talk, 
which covered a description of the 
different types of receiving sets, from the 
crystal to the king of them all, the 
super-heterodyne, touching upon the 
merits of each and explaining their 
proper application. He was followed 
by Mr. Flewelling, who gave a splendid 
discussion on the use of good apparatus 
and careful construction, clearing up 
considerable confusion in regard to the 
reason why some radio enthusiasts get 
good results, while others fail. Mr. 
Grimes then took the floor and told of 
the development of radio, starting with 
the time when Alexander Graham Bell 
transmitted the first radio message on 
a beam of light and stated that at the 
present day we are still transmitting 
radio messages on invisible beams of 
light. Mr. Pearne followed Mr. Grimes 
with a brief talk on his experience in 
building the Grimes Inverse Duplex. 
The next and last speaker was Mr. 
Milo Gurney, who started in to chastise 
two offenders who had caused some 
interference with spark sets and then 
told what the A. R. R. L. had done to 
clear up interference of this kind, having 
finally succeeded in making the air 
practically clear during the hours of 
broadcasting. He also explained that 
most of the code messages heard during 
these quiet hours were sent out by ships 
on both the Atlantic and Pacific oceans. 
The party broke up at the Athletic Club, 
an hour or so later, all agreeing that it 
was the end of a perfect day. 

The Chairman of the meeting was Ed- 
ward T. Howell, 9CVI, President of The 
Milwaukee Radio Amateurs' Club, Inc. 



SMILING EXPERTS 

Frank D. Pearne, on left, and David W. Grimes as they were snapped at 
Milwaukee where they attended a radio dinner with other wireless notables 
as guests of the Milwaukee Radio Club and of the Allen-Bradley Co. Mr. 
Pearne is Technical Editor of Radio Age and Mr. Grimes is the famous 
"Inverse Duplex" genius. 



Station for Farmers 

Sears-Roebuck Agricultural Foundation 
is building a new broadcasting station 
which is being erected by the foundation 
to broadcast agricultural as well as enter- 
tainment programs. Samuel R. Guard, 
is director of the foundation. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



47 



The new station will be located on the 
main building, in Chicago, using the 
fourteen-story tower for one aerial post. 
Another post of equal height will be 
erected on the opposite side of the build- 
ing. The station, unless other arrange- 
ments are made, will have a wave length 
of 448 meters, and will be the largest 
made and sold by the Western Electric 
Company. It will carry a class "B" li- 
cense, the highest issued by the govern- 
ment. The studio will be located on the 
eleventh story of the tower, with the oper- 
ating room on the fourteenth floor. In 
addition to the main studio, there will 
be a branch down town in the loop dis- 
trict, with special leased wires through 
the city to points of advantage for the 
entertainment features of the program, 
which will include the best music and 
theatrical talent. By having the station 
located in the open district and free from 
the absorption by all buildings, it is es- 
timated that it will be possible to put 
more energy in the air than any other 
station in Chicago. 

Theatrical stars will bring the stage 
to the farmers' parlor, and there will be 
bedtime stories for the country kiddies. 
An interpretation of market trends and 
a current events feature, explaining what 
is going on in agriculture all over the 
world will be given, according to Mr. 
Guard. This new station, which will 
be the only one in the United States 
broadcasting exclusive agricultural pro- 
grams, will be completed early in March. 
L. P. Dryden will be director of the studio. 



Airplane Telephony 

By LLOYD JACQUET 

While speeding westward at a 120 
miles an hour rate, Airmail Pilot Jack 
Knight, in his radiophone equipped 
plane, convinced officials of the Post 
Office Department and engineers of the 
Westinghouse Electric Company that 
two-way radio telephone communica- 
tion between an airship and the field 
was possible. 

Jack Knight left Omaha, bound for 
North Platte, one of the regular stops 
on the transcontinental air route, on 
a test flight early this week. Eugene 
Sibley, radio traffic supervisor of the 
United States Airmail Service, was his 
only passenger. The radio equipment 
in the plane had been tested previous to 
his taking off, and found to be in perfect 
operating condition. 

The airmail field at Omaha, which is 
the headquarters of the superintendent 
of the western division of the airmail 
service, had been chosen by General 
Superintendent Carl F. Egge as the 
place at which the new one kilowatt 
Westinghouse radiophone transmitter 
was to be installed. As Omaha is prac- 
tically the midpoint on the New York- 
San Francisco journey, the location of 
this powerful unit is ideal from a point 
of centralized communication east and 
west. It was by means of this specially 
designed and built set that the officials 
of the airmail field at Omaha kept in 
touch with Knight's plane as he was 
flying to North Platte. 

For nearly three hours, that is, the 
time it took for the pilot to fly between 



the United States Airmail fields at Omaha 
and North Platte, signals were exchanged 
between the speeding airship and the 
men in the radio room of the Omaha 
field. A schedule had been worked out, 
whereby the pilot would "report" to 
the division superintendent the progress 
of the plane as it speeded across Nebraska. 
The voice of the pilot was received 
clearly, and was received on a loud 
speaker in the radio room of the field, 
so that Superintendent D. B. Colyer, 
special assistant of Postmaster General 
J. V. Maggee, Mayor J. C. Dahlman, 
of Omaha, R. L. Davis, radio engineer 
of the Westinghouse Electric, members 
of the press, and many others followed 
the progress of the plane with a map. 

When the Post Office Department 
undertook to transport mail by means 



of airplanes, the necessity for some means 

of communication between fields, and 

between planes and fields was plainly 

{Continued on page 49.) 




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Logic Proves 
It's Better 




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THEREFORE, it follows that if the 
Spiderweb Variometer or Variocoupler could 
be built with easy mechanical operation and 
perfect insulation it would be better than 
layer type. So we built ours that way. 

PFANSTIEHL TUNING UNIT was 
fully described by Frank D. Pearne in the 
February issue of Radio Age, page 15, 
isometric sketch and the diagram of the 
Pfanstiehl Hook-up. 




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PFANSTIEHL SILENCERS "trap the enemy 
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List Wave 

Turns Price Length 

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P-202 35 .59 125-470 

P-203.__ 50 .65 170-650 

P-204 75 .74 220-960 

P-205 100 .90 300-1300 

P-206.__ 150 1.10 470-1980 

Pfanstiehl Ultra Audion $0.95 

Pfanstiehl Reinartz..... 1.75 

(The Pfanstiehl Inductance is a highly 
effective coil f>r the Reinartz circuit.) 

Above items at all good dealers or 
sent postpaid. 

Pfanstiehl 

Radio Service Co. 



HIGHLAND PARK, ILL. 
CHICAGO OFFICE, 33 SOUTH CLINTON STREET 



48 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



RCA Tells Why Tubes Dropped 



HEREWITH is published a part of 
an open letter issued by David 
Sarnoff, of the Radio Corporation 
of America. Because of certain facts 
and conditions well known to the radio 
industry the drop in the price of vacuum 
tubes was not surprising but it caused 
so much interest among tradesmen and 
buyers of receiver equipment that some 
space is given to it. The letter follows: 

f\ N January 11,1924, the Radio Corpor- 
^-J ation of America reduced the list price 
of its standard line of receiving radio- 
trons from $6.50 to $5.00 each. Notice 
of this reduction was given at the same 
time by telegraph to all our distributors, 
and no one was given any advance infor- 
mation or special advantages in connec- 
tion with this change. The public was 
informed through suitable advertise- 
ments in the leading newspapers of the 
country on the same day that the lower 
price became effective. 

We have heard from a number of our 
distributors, who have frankly expressed 
themselves with regard to this matter, 
and while some have complimented us 
on the action taken, there are others who 
criticised our policy in this particular in- 
stance. 

The purpose of this communication is 
to inform our distributors and dealers, 
with equal frankness, of the circum- 
stances obtaining in this case, which have 
led to the position taken by the Radio 
Corporation. 

Why was the list price of radiotrons 
reduced from $6.50 to $5 each? 

1. Because the RCA desired to give 
to the public, as quickly as possible, the 
benefits of a reduction in price on an ar- 
ticle of merchandise which had become 
standardized in manufacture and on 
which manufacturing economies on tubes 
now being produced were made possible 
through continued and increased public 
demand for this article. 

2. Because the RCA desired to enable 
its distributing channels to be in a posi- 
tion to offer to the public the best known 
tube in the world today at a price which 
would discourage "bootlegging," in- 
fringement and unfair trade practices on 
the part of those whose present activities 
in the radio market tend to destroy 
rather than build up public confidence. 

3. Because the RCA believes that 
this decrease in price will bring increased 
sales and thereby enable more balanced 
production at the factory, less fluctua- 
tions on the market and greater popular- 
ity for radio itself; all of which advan- 
tages are distributed over the manu- 
facturer, distributor, dealer, consumer 
and, therefore, over the industry as a 
whole. 

Why did the RCA put this reduction 
into effect overnight without previous no- 
lice? 

1. Because it desired to avoid any 
possibility of individual advantage on the 
part of one distributor or dealer at the 
expense of another, which might have re- 



sulted from advance notice of the con- 
templated reduction. 

2. Because previous experience on 
the part of other manufacturers, as well 
as ourselves, has amply demonstrated the 
impracticability of avoiding the undesir- 
able effects referred to in the preceding 
paragraph, except by an instantaneous 
overnight notice in the case of merchan- 
dise having national distribution, as in 
this case. 

3. Because it has been suggested to 
us from time to time in general discus- 
sion and without reference to any par- 
ticular case, that where a change in price 
is to be made, the trade generally pre- 
fers to have it become effective over- 
night through simultaneous notification. 

What is the financial effect on the yobber 
and dealer as a result of this price change? 

1. While we fully understand that as 
a bookkeeping proposition the distribu- 
tor measures his loss on stock in terms of 
what he would have earned if the price 
change had not been put into effect, 
nevertheless it must be recognized that 
this is not the true measure of actual 
financial loss. The actual loss is the dif- 
ference between the price paid for the ar- 
ticle and the price at which it is sold, 
minus the cost of doing business. In this 
particular case, as a result of the change 
which went into effect, the jobber will 
receive in cash fifteen cents less than he 
paid for the tube he had in stock on Jan- 
uary 10, 1924. On the same basis, the 
dealer will receive thirteen cents more 
than the actual cost to him for the tube 
he had in stock on the same date. 

Why did not the RCA make an adjust- 
ment on jobbers' and dealers stocks of tubes 
in inventory at date of reduction in price? 

1. Because in this particular case the 
dealer would probably have felt justified 
in claiming an adjustment on his stock 
of tubes if an adjustment were made to 
distributors on their stocks. For the 
RCA to have adjusted on dealer's and 
distributor's stock of tubes, would have 
meant a financial loss to this corporation 
greater than it feels its distributors and 
dealers have a right to expect it to assume 
in view of all the circumstances recited 
above and in the paragraphs to follow. 

2. Because the Radio Corporation of 
America, in the interest of its distributors 
and dealers, has always found it neces- 
sary itself to carry a large inventory — 
amounting to several hundred thousand 
radiotrons — in order that distribution 
should be prompt, uniform, and satis- 
factory to the trade and the public. 
The RCA uncomplainingly carries this 
heavy investment even in slack periods 
and now takes a very large loss itself, re- 
sulting from the reduction. 



must one expend for tubes, batteries, 
aerial and for phones? 

Just after Christmas, a woman called 
the Chesapeake & Potomac Telephone 
Company and asked for aid, explaining 
that although she knew WCAP was 
broadcasting, she could not get it on 
her new set. 

The operator inquired if the tubes 
lit up, whereupon she asked what they 
were, and being told, said there didn't 
seem to be any in the set. Further in- 
quiry showed that she had neither tubes, 
batteries, aerials nor phones, but that 
the donor of the gift supposed he had 
presented her a radio receiver ready 
for operation. 

Other examples, such as this, convince 
of the need of better salesmanship and 
also of better advertising, for some ad- 
vertisements are found to be misleading, 
although probably not intended to be 
deceptive. The dealer who sold the 
above set lost the sale of accessories and 
the purchaser was embarrassed and dis- 
appointed when he learned that vital 
parts were missing from the "set." The 
word "set" implii i that it is a complete 
entity. An automobile salesman would 
not sell or advertise a car without a 
battery, headlights and tires; why should 
a radio salesman do so? If the set is not 
complete and ready to operate, why 
not say: "Without tubes, batteries or 
phones," as a few agencies do? Com- 
plete sets could also be advertised and 
then the purchaser would know just how 
much money he would have to spend. 



Complete Sets 

Efforts are being made to standardize 
radio apparatus and the nomenclature 
which describes sets and parts. Is it 
not time all manufacturers and dealers 
standardized descriptions of sets? When 
is a set complete? How much more 



Ship Interference 

Amateur radio operators and the broad- 
casters, it appears, have "laid off" each 
other as far as interference is concerned, 
but both are now complaining of the 
ship interference, supervisors of the De- 
partment of Commerce point out. Need- 
less to say, the ships must be permitted 
to communicate with the shore stations 
and each other, and while some of them 
may not have gotten over the idea that 
the "air" belongs to them, as it did vir- 
tually for years, they now claim with 
some justice that there are not enough 
channels for their necessary communi- 
cation. 

Ship operators report and supervisors 
agree that the wavelengths assigned to 
vessels are not all they should be. The 
300 meter wave is not sufficient; the 600 
meter wave, used for calling and for dis- 
tress signals, is always in use, and the 
706 meter wave can't possibly serve all 
the vessels operating. So far as it is 
known, it is understood that many for- 
eign ships are not yet equipped to use 
706 meters, which throws them on the 
450 or 600 meter waves. Consequently 
the ships have to resort to the 450 meter 
wave assigned them, which is right in the 
middle of the broadcasting wave band. 
They are practically forced to use this 
wavelength for their position reports 
transmitted between 7 and 11 p. m. daily. 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



49 



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For Transmission or Reception 




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(Continued from page 47) 
apparant. In fact, the need of a radio 
communication"circut for such purposes 
was well appreciated by Second Assistant 
Postmaster General Paul Henderson 
as far back as 1919, when the earliest 
airmail service experiments were per- 
formed, using a radio direction finder. 

Sence then, many developments have 
been made by the department, and more 
recently, tests have been inaugurated 
between flying planes and fields. In 
November, 1922, were begun the ex- 
periments which culminated in the 
demonstration held at the Omaha field 
nearly a year later with gratifying results. 

Due to the farsightedness of Second 
Assistant Postmaster General Hender- 
son, and to the vision of E. B. Mallory, 
radio manager of the Westinghouse 
Electric Company, the air service was 
able to conduct the first satisfactory 
experiments in communicating between 
the field and the flying plane. 

The problem of communicating be- 
tween plane and ground is a very peculiar 
one. Due to the technical limitations 
of the radio apparatus because of its 
reduced size and weight, and its opera- 
tion with reduced antenna facilities and 
available power, the range of the aerial 
set is necessarily limited. 

To reach the speeding plane from the 
ground has been equally as difficult. 
Due to the noise of the engine, local 
interference picked up by the receiver 
from the ignition and other electrical 
circuits of the motor, the use of a com- 
paratively poor antenna system, and the 
limitations of the equipment in the plane 
the accomplishment is no small one. 

The thousand-watt transmitter which 
was especially designed and built for the 
airmail service of the Post Office Depart- 
ment by the Westinghouse Electric 
Company is the first to be installed at 
any of the airmail fields. The range 
of the transmitter is estimated at about 
300 to 500 miles daylight, and up to 
1,000 miles at night. By means of this 
transmitter it is possible for the superin- 
tendents at the fields to talk to any of 
their pilots while the plane is in flight 
between fields, as these are less than 
500 miles apart. 



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1 Inductance coil — -ready wound. 

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1 VOLUME 
514 PAGES 

Compiled by 

HAltRY F. DART 

E.E. 

Formerly with the 
Western Electric 
Co., and U. S. 
Army Instructor 
of Radio. 



Technically Edited by F. H. Doane 

30,000 SOLD 

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Hundreds of illustrations and diagrams explain 
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ever receiver you build or buy. 

It contains: Electrical terms and cir- 
cuits, antennas, batteries, generators 
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every receiving hook-up, radio and audio 
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50 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



Can Radio Be Hooverized? 

By CARL H. BUTMAN 



COMPLAINTS relating to radio in- 
terference are received daily by- 
Secretary of Commerce Hoover, 
who has become a sort of foster father of 
the art, now regulated under the 1912 
law by his Bureau of Navigation. A re- 
cent and unique communication from a 
fan located on the Florida peninsula, 
where ship traffic is heard almost con- 
stantly, has caused amusement in high 
official circles. The letter which follows, 
voices a pathetic appeal from an apostle 
of Hooverism, and demonstrates the 
need for definite regulatory laws: 

"My dear Sir: 

"Help! ! ! ! ! 

"When you called upon me to con- 
serve, I conserved. When you asked me 
to sweeten my food with the milk of 
human kindness, I got indigestion using 
Florida cane syrup in my coffee. When 
you asked me to come across, I stepped 
on the gas. When you asked for help 
for Near East, I went the limit. When 
you asked for help for Russia, I sent over 
a few safety razors and barber shears. 

"I have been for you in your every 
endeavor. I have Hooverized until I 
didn't know hover who. 

"Now J want RELIEF. 

"I have seven hundred dollars invest- 
ed in a radio set. It functions perfectly 
but every program is deadened or the 
fine passages lost by the damnable inter- 
ference. 

"And this not for one night but every 
night for a year back, and from any time 
in the day until I quit in disgust. 

"Night after night I try until my pa- 
tience is exhausted to get a decent re- 
ception — and maybe for a minute, some- 
times two minutes — a song or music 
comes in as clear as a bell, and then some 
deep throated spark begins to shatter 
the atmosphere and the amplifier takes 
it up and another station is lost. Some 
damphool is playing with the keys of 
his transmitter — or telling some buddy 
or some other rumrunner that he has a 
date when on shore with some calico. 

"There must be some relief. Were 
there periods of ten minutes even when 
one could listen in to lectures, songs or 
music without interference I would have 
no complaint. But it is incessant. 

"Even when our President spoke his 
eulogy of Mr. Harding, the code kept 
jamming the atmosphere and I lost part 
of the beautiful message. Surely there 
can be some measure' to protect three 
million radio fans from this insistent in- 
terference on every wave length — fellows 
using old-time sets with a spark as wide 
as Cumberland Gap that no wave trap 
can still nor any point on variocouplers, 
three condensers and four rheostats tune 
out. 



"Dante's Inferno can be no worse than 
the noises that come to us here in the 
peninsula of Florida. 

"In relief work, in drives, in everything 
you have accomplished the seemingly 
impossible — for God's sake let us have 
relief! 

"(From a Florida Fan)." 

Mr. Hoover's answer has not been 
made known, but it is understood that 
he realizes keenly the need for more 
authority to regulate radio, both ashore 
and afloat, even though the voluntary 
agreement laid down by past radio con- 
ferences has modified the radio interfer- 
ence. Legislation defining his duties and 
setting forth rules and regulations as to 
amateur, commercial, private and other 
forms of radio communication is urgently 
desired by the secretary, as well as ad- 
ditional appropriations and personnel for 
better and more frequent inspection of 
stations causing interference. 

Chief Radio Supervisor W. D. Terrill, 
in connection with the recent radio con- 
ference on shipping interference, says 
that coastal stations near New York and 
most of the shippers have agreed not to 
use the 450 meter wave but to make 
greater use of the 600 and 706 meter 
channels, thus eliminating much spark 
interference. Other conferences in San 
Francisco and Seattle, are also reported 
to have come to practically the same 
agreement; using the longer wave lengths 
when off our coasts. 



Types of Receivers 

By A. K. PHILLIPPI, Radio Engineer, 
Westinghouse Electric and Manu- 
facturing Company 

THE radio columns of the daily papers 
are filled with questions asking for 
possible results from certain receiving 
sets; whether they are good for one 
hundred miles or a thousand, whether 
they will get this station or that, and a 
host of other details. It is evident 
that a short description of the different 
types of receivers and what may be 
expected of each will be appropriate, and 
will enable many to make a better selec- 
tion which will more adequately meet 
the individual's needs. 

A radio receiving set is an instrument 
which, when connected to an antenna, 
either of the elevated wire or loop type, 
is capable of converting the high fre- 
quency ether or wireless waves into air 
or sound waves, thus enabling the listener 
to hear speeches, broadcast programs or 
telegraphy. 

There are many types of radio re- 
ceivers, varying in sensitivity, selectivity, 
price and ease of operation. 

The crystal receiver is the type most 
commonly used and the least expensive. 



This consists of a tuning coil and a 
crystal detector. Some of these have 
sharp tuning, or are more selective, 
while others have broad tuning. Sharp 
tuning is to be preferred, of course, as it 
helps to eliminate stations to which one 
does not wish to listen. The range of the 
crystal set is small, and on the average 
it is capable only of receiving signals 
within a maximum of fifty miles from 
the broadcasting station; this range 
depends entirely on the power of the 
transmitting station, the size of antenna 
and the sensitivity of crystal. With 
this type of instrument the music and 
other programs are almost an exact 
reproduction of that delivered into the 
transmitter, as very little distortion 
occurs. It is used near a broadcasting 
station and requires a large antenna for 
best results. Head phones must be used 
with this set. Receivers of this class are 
gradually losing their popularity for, 
as the owner becomes most interested in 
radio, he feels hampered with only a 
crystal set and wishes to reach farther 
out into ether for more distant stations. 

Vacuum tube receivers. — The vacuum 
tube receiver consists of practically the 
same apparatus as the crystal receiver, 
except that a vacuum tube is used instead 
of a crystal for a detector. This set has a 
distinct advantage over the crystal set 
in as much as the detector remains 
adjusted once it is set, while the crystal 
requires careful adjustment and is easily 
jarred from a sensitive position. Another 
advantage of the vacuum set is that it is 
more sensitive than the crystal. Its 
sensitivity is, however, still limited, and 
head phones must be used. 

Detector amplifier receivers. — This in- 
strument is one in which the signals are 
detected by either a crystal or a vacuum 
tube. The signals are then strengthened 
by means of one or more stages of vacuum 
tube amplification, and may be built up 
to such an extent as to permit the use of 
a loud speaker. 

Regenerative receivers. — By means of 
the Armstrong or regenerative circuit, 
amplification and detection with a single 
tube may be obtained in a receiver, which 
will give great sensitivity for distant 
signals. This set differs from others in 
that a regenerator or tickler coil is used 
and its function is to build up or amplify 
the detected signal. By the use of the 
instrument very weak signals may be 
heard. This set requires a little more 
careful adjustment than the other re- 
ceivers mentioned. 

Care should be taken in operating it to 
use its good qualities and not abuse 
them. With a little experience the 
operator will find that when the tickler 
or regenerator knob is turned to a cer- 
tain place, the signals received are clear 
and strong. This is the point of maxi- 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



51 



Corrected List of U. S., Cuban and Canadian 

Broadcasting Stations 



Complete Each Issue 

THE list of broadcasting stations on these pages is brought up to date each month by additions of 
new stations and deletion of those which have suspended operation. The list is the product of a 
vast volume of correspondence and its completeness is due in large measure to the assistance 
of our special news service in Washington, D. C. Suggestions, corrections and additional data will 
be welcomed from readers and broadcasters. 



KDKA Westinghouse Electric & Mfg. Co East Pittsburgh 326 

KDPM Westinghouse Electric & Mfg. Co Cleveland, Ohio 270 

KDPT Southern Electrical Co San Diego. Calif. 244 

KDYL Telegram Publishing Co Salt Lake City, Utah 360 

KDYM Savoy Theatre San Diego, Calif. 244 

KDYQ Oregon Institute of Technology Portland. Oreg. 360 

KDYW Smith Hughes & Co ....Phoenix, Ariz. 360 

KDYX Star Bulletin Honolulu. Hawaii 360 

KDZB Frank E. Siefert Bakersfield, Calif. 240 

KDZE Rhodes Department Store Seattle, Wash. 270 

KDZF Automobile Club of Southern California Los Angeles, Calif. 278 

KDZI Electric Supply Co . Wenatchee, Wash. 360 

KDZQ Nichols Academy of Dancing Denver, Colo. 360 

KDZR BeUingham Publishing Co Bellingham. Wash. 261 

KFAD McArthur Bros. Mercantile Co Phoenix, Ariz. 360 

KFAE State College of Washington Pullman, Wash. 330 

KFAF Western Radio Corp Denver, Colo. 360 

KFAJ University of Colorado _ .....Boulder, Colo. 360 

KFAN The Electric Shop Moscow. Idaho 360 

KFAR Studio Lighting Service Co. (0. K. Olsen) Hollywood. Calif. 280 

KFAU Independent School Dist. of Boise City, Boise High School, Boise. Idaho 270 

KFAW The Radio Den (W. B. Ashford) Santa Ana, Calif. 280 

KFAY W. J. Virgin.... Jiledford. Ores. 283 

KFBB F. A. Buttrey & Co Havre, Mont. 360 

KFBC W. K. Azbill San Diego. Calif. 278 

KFBE Reuben H. Horn San Luis Obispo. Calif. 360 

KFBG First Presbyterian Church Tacoma, Wash. 360 

KFBK Kimball-Upson Co Sacramento, Calif. 283 

KFBL Leese Bros. Everett, Wash. 224 

KFBS Trinidad Gas & Electric Supplv Co. and the Chronicle News 

Trinidad, Colo. 360 

KFBU The Cathedral (Bishop N. S. Thomas) Laramie, Wyp. 283 

KFCB Nielsen Radio Supply Co .Phoenix, Ariz. 238 

KFCF Frank A. Moore Walla Walla, Wash. 360 

KFCH Electric Service Station (Inc.) Billings, Mont. 360 

KFCM Richmond Radio Shop (Frank T. Doeing) Richmond, Calif. 360 

KFCP Ralph W. Flygare Ogden, Utah 360 

KFCV Fred Mahaffey. Jr : Houston, Tex. 360 

KFCY Western Union College I.eMars, Iowa 252 

KFCZ Omaha Central High School Omaha, Nebr. 258 

KFDA Adler's Musio Store Baker. Oreg. 360 

KFDD St. Michaels Cathedral Boise. Idaho 252 

KFDH University of Arizona _ Tuscon, Ariz. 360 

KFDJ Oregon Agricultural College Corvallis. Oreg. 360 

KFDL Knight-Campbell Music Co Denver. Colo. 360 

KFDO H. Everett Cutting JBozeman, Mont. 248 

KFDR Bullocks' Hardware & Sporting Goods (Robert G. Bullockh.York, Nebr. 360 

KFDV Gilbrech & Stinscm _ Fayetteville, Ark. 360 

KFDX First Baptist Church Shreveport, La. 360 

KFDY South Dakota State College of Agriculture and Mechanics Arts 

Brookings, S. Dal;. 360 

KFDZ Harry O. Iverson Minneapolis, Minn. 231 

KFEC Meier & Frank Co _ Portland, Oreg. 360 

KFEJ Guy Greason — Tacoma, Wash. 360 

KFEL Winner Radio Corp _ .Denver, Colo. 360 

KFEQ J. L. Scroggin Oak, Nebr. 360 

KFER Auto Electric Service Co _ Fort Dodge, Iowa 23( 

KFEV Radio Electric Shop Douglas, Wyo. 263 

KFEX Augsburg Seminary Minneapolis, Minn. 261 

KFEY Bunker Hill & Sullivan Mining & Concentrating Co Kellogg. Idaho 360 

KFEZ American Society of Mechanical Engineers (F, H. Schubert) 

St. Louis. Mo. 360 

KFFB Jenkins Furniture Co Boise, Idaho 240 

KFFE Eastern Oregon Radio Co Pendleton, Oreg. 360 

KFFO Dr. E. H. Smith Hillsboro. Oreg. 229 

KFFQ Marksheffel Motor Co Colorado Springs, Colo. 360 

KFFR Nevada State Journal (Jim Kirk) Sparks, Nev. 226 

KFFV Graceland College Lamoni, Iowa 360 

KFFX McGraw Co Omaha, Nebr. 278 

KFFY Pincus & Murphy Alexandria, La. 275 

KFFZ Al. G. Barnes Amusement Co Dallas, Tex. (portable) 226 

KFGC Louisiana State University Baton Rouge, La. 254 

KFGD Chickasha Radio & Electric Co Chickasha, Okla. 248 

KFGH Leland Standford University Stanford University, Calif. 360 

KFGJ Missouri National Guard. 138th Infantry St. Louis, Mo. 266 

KFGL Arlington Garage Arlington. Oreg. 234 

KFGQ Crary Hardware Co _ Boone, Iowa 226 

KFGV Heidbreder Radio Supply Co Utica, Nebr. 224 

KFGX First Presbyterian Church , Orange, Tex. 250 

KFGZ Emmanuel Missionary College Berrien Springs, Mich. 268 

KFHA Western State College of Colorado Gunnison, Colo. 252 

KFHB Rialto Theater (P. L. Beat-dwell) Hood River, Oreg. 280 

KFHD Utz Electric Shop Co St. Joseph. Mo. 226 

KFHF Central Christian Church Shreveport. La. 266 

KFHH Ambrose A. McCue Neah Bay, Wash 283 

KFHJ Fallon & Co _ Santa Barbara. Calif. 360 

KFHR Star Electric & Radio Co Seattle. Wash. 270 

KFHS Clifford J. Dow Xihue. Hawaii 275 

KFHX Robert W. Nelson Hutchinson, Kans. 229 

KFI Earle C. Anthony (Inc.) Los Angeles, Calif. 469 

KFID Ross Arbuckle's Garage Iola, Kans. 246 

Benson Polytechnic Institute Portland, Oreg. 360 

KFIL Windisch Electric Farm Eouipn.ent Co Louisburg, Kans. 234 

KFIO North Central High School „ Spokane, Wash. 252 

KFIQ Yakima Valley Radio Broadcasting Association. Yakima, Wash. 224 

KFIU Alaska Electric Light & Power Co Juneau, Alaska 226 

KFIV V. II. Broyles _ Pittsburg, Kans. 240 

KFIX Reorganized Church of Jesus Christ of Latter Day Saints 

„,_,, _ ., Independence, Mo. 240 

KFIZ Daily Commonwealth and Oscar A. Huelsman J"on du Lac. Wis. 273 

KFJB Marshall Electrical Co Marshalltown. Iowa 248 

KFJC Seattle Post Intelligencer Seattle. Wash. 233 

KFJF National Radio Manufacturing Co Oklahoma City. Okla. 252 

KFJI Liberty Theatre (E. E, Marsh) Astoria, Oreg. 252 

KFJK Delano Radio and Electric Co Bristow. Okla. 233 

3E J .. ,Taro ' sar 'K Manufacturing Co Ottumwa. Iowa 242 

KFJM University of North Dakota _ Grand Forks. N. Dak. 229 

KFIQ Valley Radio, DIv. of Elect. Constr. Co _ Grand Forks, N. D. 280 

KFJR Ashley C. Dixon & Son _ Stevensville. Mont, (near) 258 

KFJV Thomas H. Warren Dexter, Iowa 224 

KFJW Le Grand Radio Co Towandn, Kans. 226 

KFJX Iowa State Teachers' College. Cedar Falls, Iowa 229 

KFJY Tunwall Radio Co _ Fort Dodge, Iowa 248 

KFJZ Texas National Guard. One hundred and twelfth Cavalry 

Fort Worth. Texas 254 



KFKA Colorado State Teachers College Greeley, Colo. 248 

KFKB Brinlcley-Jones Hospital Association Mill'ord, Kans. 286 

KFKQ Conway Radio Laboratories (Ben II. Woodruff) Conway, Ark. 224 

KFKV F. F. Gray _ Butte. Mont. 283 

KFKX Westinghouse Electric & Manufacturing Co Hastings, Nebr. 341 

KFKZ Nassour Bros. Radio Co Colorado Springs. Colo. 234 

KFLA Abner R. Willson. Butte. Mont. 283 

KFLB Signal Electric Manufacturing Co Menominee, Mich. 248 

KFLD Paul E. Greenlaw _ Franklinton, La. 234 

KFLE National Educational Service. Denver, Colo. 268 

KFLH Erickson Radio Co Salt Lake City. Utah 261 

KFLP Everette M. Foster Cedar Rapids, Iowa 240 

KFLQ Bizzell Radio Shop Little Rock. Ark. 261 

KFLR University of New Mexico. ....Albuquerque, N. Mex. 254 

KFLU Rio Grande Radio Supply House San Benito, Texas 236 

KFLV Rev. A. T. Frykman. Rockford, 111. 229 

KFLW Missoula Electric Supply Co Missoula, Mont. 234 

KFLX George Rov Clough Galveston, Tex. 240 

KFLY Fargo Radio Supply Co Fargo. N. Dak. 231 

KFLZ Atlantic Automobile Co Atlantic. la. 273 

KFMQ University of Arkansas Fayetteville, Ark. 263 

KFMR Morningside College.... Sioux City. Iowa 261 

KFMS Freimuth Dept. Store Duluth, Minn. 275 

KFMT Dr. George W. Young Minneapolis, Minn. 231 

KFMU Stevens Bros San Marcos, Texas 240 

KFIWW M. G. Sateren Houghton. Mich. 266 

KFMX Carleton College Northfleld, Minn. 283 

KFMY Boy Scouts of America Long Beach. Calif. 229 

KFMZ Roswell Broadcasting Club RosweU. N. M. 252 

KFNC Echo Park Evangelistic Ass'n., Inc Los Angeles, Calif. 278 

KFNG Wooten's Radio Shop '. Coldwater, Miss. 254 

KFNH State Teachers College Springfield. Mo. 236 

KFNJ Warrensburg Electric Shop Warrensburg. Mo. 234 

KFNL Radio Broadcast Ass'n Paso Robles, Calif. 240 

KFNV L. A. Drake Battery and Radio Supply Shop Santa Rosa, Cal. 234 

KGB Tacoma Daily Ledger Tacoma, Wash. 252 

KGG Hallock & Watson Radio Service Portland, Oreg. 360 

KGN Northwestern Radio Mfg. Co _ Portland, Oreg. 360 

KGO General Electric Co Oakland, Calif. 312 

KGU Marion A. Mulrony Honolulu, Hawaii, Waikiki Beach 360 

KGW Portland Morning Oregonian Portland, Oreg. 492 

KGY St. Martins College (Rev. Sebastian Ruth) Lacy. Wash. 258 

KHJ Times-Mirror Co _ Los Angeles, Calif. 395 

KHQ Louis Wasmer Seattle, Wash. 360 

KJQ C. O. Gould Stockton. Calif. 360 

KIR Northwest Radio Service Co Seattle, Wash. 270 

KJS Bible Institute of Los Angeles _ Los Angeles. Calif. 360 

KLS Warner Brothers Radio Supplies Co Oakland. Calif. 360 

KLX Tribune Publishing Co Oakland. Calif. 509 

KLZ Reynolds Radio Co Denver, Colo. 509 

KMJ San Joaquin Light & Power Corp Fresno, Calif. 273 

KMO Love Electric Co Tacoma, Wash. 360 

KNT Grays Harbor Radio Co. (Walter Hemrich) Aberdeen. Wash. 263 

KNV Radio Supply Co ...Los Angeles. Calif. 256 

KNX Electric Lighting Supyly Co Los Angeles, Calif. 360 

KOB New Mexico College of Agriculture & Mechanic Arts 

State College, N. Mex. 360 

KOP Detroit Police Department Detroit, Mich. 280 

KPO Hale Bros San Francisco. Calif. 423 

KQP Apple City Radio Club Hood River, Oreg. 360 

KQV Douhleday-Hill Electric Co Pittsburgh, Pa. 360 

KQW Charles D. Herrold San Jose, Calif. 360 

KRE V C Battery & Electric Co Berkeley, Calif. 278 

KSO Post Dispatch (Pulitzer Pub. Co.) St. Louis, Mo. 546 

KSS Prest & Dean Radio Co. and Radio Research Society of Dong Beach, 

Calif Long Beach. Calif. 360 

KTW First Presbyterian Church _ Seattle. Wash. 360 

KUO Examiner Printing Co San Francisco, Calif. 360 

KUS City Dye Works & Laundry Co Los Angeles. Calif. 360 

KUY Coast Radio Co _E1 Monte, Calif. 256 

KWG Portable Wireless Telephone Co Stockton, Calif. 360 

KWH Los Angeles Examiner _ Los Angeles. Calif. 360 

KXD Modesto Herald Publishing Co Modesto, Calif. 252 

KYQ Electric Shop .Honolulu. Hawaii 366 

KYW Westinghouse Electric & Mfg. Co Chicago. 111. 536 

KZM Preston D. Allen _ Oakland, Calif. 360 

KZN The Deseret News Salt Lake City. Utah 360 

KZV Wenatchee Battery & Motor Co Wenatchee, Wash. 360 

WAAB Valdemar Jensen New Orleans. La. 268 

WAAC Tulane University _ ......New Orleans, La. 360 

WAAD Ohio Mechanics Institute Cincinnati, Ohio 360 

WAAF Chicago Daily Drovers Journal _ Chicago, 111. 286 

WAAK Gimbel Brothers Milwaukee. Wis. 280 

WAAM I. R. Nelson Co Newark. N. J. 263 

WAAN University o Mfissouri _ Columbia. Mo. 254 

WAAW Omaha Grain Exchange Omaha. Nebr 360 

WABA Lake Forest College Lake Forest. HI. 266 

WABB Dr. John B. Lawrence Harrisburg, Pa. 266 

WABD Parker High School Dayton, Ohio 283 

WABE Young Men's Christian Association Washington, D. C. 283 

WABG Arnold Edwards Piano Co _ Jacksonville, Fla. 248 

WABH Lake Shore Tire Co Sandusky. Ohio 240 

WABI Bangor Railway & Electric Co Bangor, Me. 240 

WABK First Baptist Church Worcester. Mass. 252 

WABL Connecticut Agricultural College. Storrs. Conn. 283 

WABM F. E. Dohcrty Automotive and Radio Equipment Co Saginaw, Mich. 254 

WABN Waldo C. Grover.. _ La Crosse Wis. 244 

WABO Lake Avenue Baptist Church Rochester. N. Y. 252 

WABP Robert F. Weinjg Dover. Ohio 266 

WABQ Haverford College Radio Club Ilavrrford Pa 261 

WABR Seott High School. N. W. B. Folev Toledo, Ohio 270 

WARS Essex Manufacturing Co _ Newark. N. J 244 

WABT Holiday-Hall. Radio Engineers Washington. Pa. 252 

WABU Victor Talking Machine Co Camden, N. J. 226 

WABV John II. DeWilt. Jr _ Nashville, Tenn. 263 

WARW College of Wooster Wooster, Ohio 234 

WABX Henry B. Jov Mt i 'I. ■mens. Mich. 270 

WABY John Magaldi, Jr Philadelphia. Pa. 242 

WABZ Coliseum Place Baptist Church New Orleans. La. 263 

WBAA Purdue University West Lofavette, Ind. 360 

WRAD Sterling Electric Co Minneapolis. Minn. 360 

WRAH The Dayton Co Minneapolis. Minn. 417 

WRAM Wireless 1'hnno Corp ...J'aterson, N. J. 244 

WRAO James Millikin University Decatur, 111 360 

WRAP Wortham-^arter Publishing Co. (Star Telegram) Fort Worth. Tex. 476 

WPAV Erner f.- Hopkins Co Columbus, Ohio 390 



52 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



mum regeneration and by going past 
this point the sound becomes mushy. 
This mushiness indicates that the maxi- 
mum regeneration point has been passed 
and that the receiver is oscillating. 
This not only destroys the quality of the 
signal but by radiating from the antenna 
a certain amount of energy, interferes 
with the neighbor's proper reception of 
the signal. This misuse has caused con- 
siderable unjust criticism of this type 
of receiver. 

The regenerative loud speaking re- 
civer combines the good qualities of the 
detector amplifier and the regenerative 
receiver, making possible the amplifica- 
tion of weaker distant signals to such an 
extent that the volume furnished is 
ample to operate a loud speaking device. 
One of the advantages offered by this 
instrument is that a small antenna may 
be used with no appreciable decrease 
in signal strength and the selectivity is 
increased, thus making it possible to 
tune out more easily the interfering 
stations. 

'* Radio frequency receivers. — As this 
type of instrument, which is quite new 
to the majority of radio fans, can be used 
on a loop or short antenna it has helped 
fill the need for a set that can be used 
in a congested district such as in apart- 
ment houses or in places where the homes 
are so close together as to make it almost 
impossible to erect an antenna. 

By using radio frequency amplifica- 
tion ahead of the detector tube, the radio 
waves are amplified before they are 
detected. Two or more stages of radio 
frequency are equal to regeneration, 
which means that to get the same results, 
one must have more tubes and batteries 
to operate this type. Instruments of 
this nature have been designed in cabi- 
nets which can be moved about the 
room with the same ease as a phonograph 
cabinet. 



No Rheostats 



Armstrong's Radio Muffler 



THE other day Major Edwin H. 
Armstrong visited the office of the 
Chief Supervisor of Radio in Washington. 
The Major has cut loose from radio for 
a while and with his wife is en route 
south in his machine, where he plans a 
month's vacation and honeymoon in 
Florida. 

Future activities of the major, it is 
understood, will be devoted to a large 
extent in remedying interference troubles 
said to be caused by his famous regenera- 
tive circuit. A large amount of the 
difficulty encountered, it is believed, is 
due to poor manipulation, but he suggests 
the use of an additional tube of radio 
frequency, as a "muffler." Just as in 
automobiles where excess noises are 
eliminated by the use of an engine 
muffler, in the operation of the regenera- 
tive sets, a radio muffler can be incorpo- 
rated. One exception is noted; in the 
automobile the muffler is placed after 
the engine, behind it, so to speak, while 
in a radio set the "muffler" should be put 
in front or before the regeneration. 





The above photographs picture a method used by a radio fan to elimi- 
nate controls for the filaments of the tubes. The cartridge types of re- 
sistance are of the proper value to be used instead of rheostats, thereby 
making the use of four extra controls unnecessary. The circuit is the 
conventional single circuit using a variocoupler as tuner. The panel view 
shows how simple the control of this set is. (Kadel & Herbert Photo.) 



Hints on Transformer Shielding 



When the magnetic or electrostatic 
field of one transformer is so located that 
it passes into the windings of the adjacent 
transformer, the first induces currents 
in the second which cause noises and 
which forms a by-pass around the ampli- 
fying tubes so that all of the energy is 
not amplified in the tubes. Where 
possible, the tubes and transformers 



should be spaced about 5 1-2 inch to 6 
inch centers, but where so much room 
is not available we may have to resort 
to shielding the tubes and transformers 
by grounded metal partitions. The 
shielding, however, is not desirable since 
it causes losses and usually interferes 
with the proper arrangement of the wir- 
ing. 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



68 



Corrected List of U. S., Cuban and Canadian 
Broadcasting Stations 



WBAX 

WBAY 

WBBA 

WBBD 

WBBE 

WBBF 

WBBF 

WBBG 

WBBH 

WBB1 

WBBJ 

WBBK 

WBBM 

WBBN 

WBBO 

WBBQ 

WBBR 

WBBT 

WBBU 

WBL 

WBR 

WBS 

WBT 

WBZ 

WCAD 

WCAE 

WCAG 

WCAH 

WCAJ 

WCAK 

WCAL 

WCAM 

WCAO 

WCAP 

WCAR 

WCAS 

WCAT 

WCAU 

WCAV 

WCAX 

WCAY 

WCAZ 

WCBA 

WCBC 

WCBD 

WCK 

WCM 

WCX 

WDAE 

WOAF 

WDAG 

WDAH 

WDAK 

WDAO 

WDAP 

WDAR 

WDAS 

WDAU 

WDAY 

WDBC 

WDM 

WDZ 

WEAA 

WEAF 

WEAH 

WEAI 

WEAJ 

WEAM 

WEAN 

WEAO 

WEAP 

WEAR 

WEAS 

WEAU 

WEAY 

WEB 

WEV 

WEW 

WFAA 

WFAB 

WFAF 

WFAH 

WFAJ 

WFAM 

WFAN 

WFAQ 

WFAT 

WFAV 

WFI 

WGAL 

WGAN 

WGAQ 

WGAW 

WGAZ 

WGI 

WGL 

WGR 

WGV 

WGY 

WHA 

WHAA 

WHAB 

WHAD 

WHAG 

WHAH 

WHAK 

WHAM 

WHAP 

WHAR 

WHAS 

WHAV 

WHAZ 

WHB 

WHK 

WHN 

WIAB 

WIAC 

WIAD 

WIAF 

WIAH 

WIAI 

WIAJ 

WIAK 

WIAO 

WIAQ 

WIAR 



John H. Stenger, Jr _.._ ..Wilkes-Barre. Pa. 

Western Electric Co ...New York, N. Y. 

Newark Radio Laboratories _ - _ -..Newark. Ohio 

Barbey Battery Servica... .Reading. Pa. 

Alfred R. Marcy _ _ - Syracuse, N. Y. 

Petoskey High School .... Petoskey. Mich. 

Georgia School of Technology _ _ Atlanta. Ga. 

Irving Vermilya ~ - Mattapoisett, Mass. 

J. Irving Bell - .....Port Huron. Mich. 

The Indianapolis Radio Club -Indianapolis. Ind. 

Neel Electric Co., P. E. Neal . ...West Palm Beach. Fla. 

Kaufmann & Baer Co .... - - -Pittsburgh, Pa. 

Frank Atlass Produce Co. Lincoln, 111. 

Blake, A. B. ..._ Wilmington. N. C. 

Mich. Limestone & Chemical Co Rogers, Mich. 

Frank Crook _ Pawtucket, R. I. 

Peoples Pulpit Asso. Rossville, N. Y. 

Lloyd Brothers Philadelphia, Pa. 

Mommouth. 111. 

...Anthony, Kans. 

Pennsylvania State Police _ _ Butler. Pa. 

D. W. May. Inc..- _ 

Southern Radio Corp _ 

Westinghouse Elec. & Mfg. Co 

St. Lawrence University 

Kaufmann & Baer Co _ 

Cylde R. Randall _. 

Entrekin Electric Co 

Nebraska Wesleyan University 



Jenks Motor Sales Co 
T & H Radio Co. 



Alfred P. DanieL... 

St. Olaf College 

Villanova College - 

Sanders & Stayman Co 

Chesapeake & Potomac Telephone Co 

Alamo Radio Electric Co _ _ 

William Hood Dunwoody Industrial Institute 

South Dakota State School of Mines 

Durham & Co _ 

J. C. Dice Electric Co 

University of Vermont 

Kesselman O'Driscoll Co. _ 

Carthage College 

Charles W. Heimbacli - .. 

University of Michigan . _ 

Wilbur G. Voliva. _ _.. 

Stix, Baer & Fuller Dry Goods Co 

University of Texas _ _ - 

Detroit Free Press...- - 

Tampa Daily Times - _ _ 

Kansas City Star. _ 

J. Laurance Martin 

Trinity Methodist Church (South) - 

The Courant . _ _... 

Automotive Electric Co - 

Board of Trade - _ - 

Lit Brothers _ _ 

Samuel A. Waite - _ _. 

Slocum Kilburn 

Radio Equipment Corp 

Kirk. Johnson & Co _ ._.. 

Church of the Covenant _.. 

James L. Bush Tuscola. 

F. D. Fallain. _ _ ... 

American Telephone & Telegraph Co _ 

Wichita Board of Trade 

Cornell University 

University of South Dakota.. 



.Newark. N. J. 

Charlotte. N. C. 

Springfield, Mass. 

_ Canton. N. Y. 

Pittsburgh, Pa. 

.New Orleans, La. 

Columbus, Ohio 

University Place, Nebr. 



Borough of North Hainfleld (W. 



..Houston, Tex. 

Northfleld, Minn. 

_ Villanova, Pa. 

Baltimore, Md. 

Washington, D. C. 

San Antonio, Tex. 

Minneapolis, Minn. 

Rapid City. S. Dak. 

Philadelphia. Pa. 

Little Rock. Ark. 

Burlington, Vt. 

.Milwaukee. Wis. 

Carthage, I1L 

Allentown, Pa. 

Ann Arbor, Mich. 

__ — Zion. ILL 

_.St Louis. Mo. 

Austin. Texas 

_ -Detroit. Mich. 

Tampa. Fla. 

Kansas City. Mo. 

Amarillo, Tex. 

.El Paso. Tex. 

Hartford. Conn. 

.Dallas, Tex. 

Chicago, I1L 

Philadelphia. Pa. 

Worcester, Mass. 

...New Bedford, Mass. 

....Fargo. N. Dak. 

Lancaster, Pa. 

Washington, D. C. 
ILL. Star Store Bldg. 

Flint. Mich. 

.New York. N. Y. 

Wichita, Kans. 

, Ithaca, N. Y. 

Vermilion, S. Dak. 



Gibson Buttilcld 

North Plainfleld 
....Providence 



N. J. 

. R. I. 

Columbus, Ohio 

Mobile. Ala. 

.Baltimore, Md. 

...Washington, D. C. 

Sioux City, Iowa 

.Houston, Tex. 

St. Louis. Mo. 

Houston, Tex. 

St, Louis. Mo. 

.Dallas. Texas 

Syracuse, N. Y. 

Poughkeepsie, N. Y. 
.Port Arthur, Texas 

AsheviUe. N. C. 

St. Cloud. Minn. 

.Hutchinson, Minn. 



Shepard Co. . 

Ohio State University 

Mobile Radio Co _ 

Baltimore American & News Publishing Co. 

Hecht Co _ _.. 

Davidson Bros. Co 

Iris Theatre (Will Horowitz. Jr.) 

Benwood Co _ 

Hurlburt-Still Electrical Co....- _ 

St. Louis University _. _ 

Dallas News & Dallas JournaL _ 

Carl F. Woese 

H. C. Spratley Radio Co 

Electric Supply Co - _ 

Hi-Grade Wireless Instrument Co 

Times Publishing Co 

Hutchinson Electric Service Co 

Missouri Wesleyan College...- _ _ Cameron. Mo. 

New Columbus College Sioux Falls, S. Dak. 

University of Nebraska. Department of Electrical Engineering 

Lincoln, Nebr. 

Strawbridge & Clothier _ _ .Philadelphia, Pa. 

Lancaster Electric Supply & Construction Co Lancaster, Pa. 

Cecil E. Lloyd.... - _ Pensacola, Fla. 

Glenwood Radio Corp. (W. G. Patterson) Shreveport, La. 

Ernest C. Albright _ -...Altoona, Pa. 

South Bend Tribune— _ South Bend. Ind. 

American Radio & Research Corp Medford Hillside. Mass. 

Thomas F. J. Howlett _ Philadelphia, Pa. 

Federal Telephone & Telegraph Co _ ....Buffalo. N. Y. 

Interstate Electrio Co New Orleans. La. 

General Electric Co...._ _.._ _ Schenectady. N. Y. 

University of Wisconsin. __ _ .Madison, Wis. 

State University of Iowa.... _ _ Iowa City. Iowa 

Clark W. Thompson. _ Galveston, Texas 

Marquette Universiy - Milwaukee. Wis. 

University of Cincinnati _ _ Cincinnati. Ohio 

Hafer Supply Co _ __ _ ....Joplln, Mo. 

Roberts Hardware Co _ Clarksburg, W. Va. 

University of Rochester (Eastman School of Music) Rochester. N. Y. 

Otta & Kuhns _ —Decatur. 111. 

Paramount Radio & Electric Co. (W. H. A. Pulus) 

Atlantio City. N. J. 

Courier-Journal & Louisville Times -...Louisville. Ky. 

Wilmington Electrical Specialty Co _ Wilmington. Del. 

Rensselaer Polytechnic Institute _ Troy, N. Y. 

Sweeney School Co _ Kansas City, Mo. 

Radiovox Co. (Warren R. Cox) _ _ Cleveland. Ohio 

George Schubel .New York, N. Y. 

Joslyn Automobile Co....- _ _ — Bockford, III. 

Galveston Tribune _ Galveston. Texas 

Howard R. Miller _ Ocean City. N. J. 

Gnstav A. DeCortin _ New Orleans, La. 

Continental Radio & Mfg. Co _ .Newton, Iowa 

Heey Stores Co _ Springfield. Mo. 

Fox River Valley Radio Supply Co. (Quinn Bros.) _ Neenah, Wis. 

Toumal-Stockman Co - Omaha. Nebr. 

School of Engineering of Milwaukee _ _ Milwaukee. Wis. 

Chronicle Publishing Co _ _ Marion. Ind. 

Paducah Evening Sun. _ Padueah, Ky 



360 
492 
240 
234 
246 
246 
270 
240 
246 
234 
258 
254 
226 
275 
250 
252 
244 
234 
224 
261 
286 
360 
360 
337 
280 
462 
268 
286 
360 
263 
360 
360 
360 
469 
360 
246 
240 
286 
360 
360 
261 
246 
280 
280 
345 
360 
360 
517 
360 
411 
263 
268 
261 
360 
360 
395 
360 
360 
244 
258 
234 
278 
280 
492 
244 
286 
283 

252 
273 
360 
360 
360 
360 
360 
360 
360 
360 
261 
476 
234 
360 
236 
360 
360 
360 
360 
258 

275 
395 
248 
360 
360 
261 
360 
360 
360 
319 
242 
380 
360 
283 
360 
280 
222 
283 
258 
283 
360 

231 
400 
360 
380 
411 
360 
360 
252 
360 
254 
234 
258 
252 
224 
278 
360 
226 
360 



WIAS Home Electric Co. JBurlington. Iowa 360 

WIAT Leon T. NoeL... _ _ Tarkio. Mo. 360 

WIAU American Trust & Savings Bant Le Mars, Iowa 360 

WIK K. & L. Electric Co. (Herbert F. Kelso and Hunter J. Lohman) 

McKeesport. Pa. 234 

WIL Continental Electric Supply Co Washington, D. C. 360 

WIP Gimbel Brothers Philadelphia, Pa. 509 

WJAD Jackson's Radio Engineering Laboratories. _ Waco. Texas 360 

WJAF Press Publishing Co - Muncie. Ind. 360 

WJAG Norfolk Daily News - _ .Norfolk. Nebr. 283 

WJAK Clifford L. White. Greentown, Ind. 254 

WJAM D. M. Perham. _ _ Cedar Rapids. Iowa 268 

WJAN Peoria Star :..„ Peoria, 111. 280 

WJAQ Capper Publications - Topeka, Kans. 360 

WJAR The Outlet Co. (J. Samuels & Bro.) _ Providence, R. I. 360 

WJAS Pittsburgh Radio Supply House _ ...Pittsburgh. Pa. 250 

WJAT Kelly-Vawter Jewelry Co _ Marshall. Mo. 360 

WJAX Union Trust Co — - _ Cleveland. Ohio 390 

WJAZ Chicago Radio Laboratory _.._ ...Chicago. 111. 448 

WJD Richard H. Howe. _ _ - Granville. Ohio 229 

WJH W. P. Boyer Washington. D. C. 273 

WJX Deforest Radio Telephone & Telegraph Co -New York, N. Y. 360 

WJY R. C. A _ _ .New York, N. Y. 405 

WJZ R. C. A _ .New York, N. Y. 455 

WKAA H. F. Paar. _ Cedar Rapids, Iowa 268 

WKAO Chas. Looff (Crescent Park) _ .East Providence, R. L 240 

WKAF W. S. Radio Supply Co.... _ - Wichita Falls. Texas 360 

WKAN United Battery Service Co Montgomery, Ala. 226 

WKAP Dutee W. Flint ._ .Cranston. R. I. 360 

WKAQ Radio Corp. of Porto Rico. _ - San Juan. P. R. 360 

WKAR Michigan Agriculture College _ East Lansing. Mich. 280 

WKAS L. E. Lines Music Co - Springfield. Mo. 360 

WKAV Laconia Radio Club... - Laconia. N. H. 254 

WKAY Brenau College _ GainesvLUe. Ga. 280 

WKY WKY Radio Shop. Oklahoma. Okla. 360 

WLAG Cutting & Washington Hadio Corp _ Minneapolis, Minn. 417 

WLAH Samuel Woodworth „ Syracuse, N. Y. 234 

WLAJ Waco Electrical Supply Co _ Waco, Texas 360 

WLAK Vermont Farm Machine Corp Bellows Falls, Vt. 360 

WLAL Naylor Electrical Co _ _ Tulsa. Okla. 360 

WLAP W. V. Jordon. _ Louisville, Ky. 360 

WLAQ Arthur E. Shilling.... _ _ Kalamazoo. Mich. 283 

WLAV Electric Shop _ _.._ .Pensacola, Fla. 254 

WLAW Police Dept., City of New York. New York. N. Y. 360 

WLAX Putnam Electric Co. (Greencastle Community Broadcasting Station) 

Greencastle, Ind. 231 

WLB University of Minnesota _ Minneapolis. Minn. 360 

WLW Crosley Manufacturing Co Cincinnati. Ohio 309 

WMAB Radio Supply Co _ Oklahoma, Okla. 360 

WMAC J. Edw. Page (Olive B. Meredith) __ Cazenovla. N. Y. 261 

WMAF Round Hills Radio Corp _ .Dartmouth. Mass. 360 

WMAH General Supply Co....- _ —Lincoln, Nebr. 254 

WMAJ Drovers Telegram Co __ Kansas City, Mo. 275 

WMAK Norton Laboratories _.._ - Lockport. N. Y. 360 

WMAL Trenton Hardware Co Trenton, N. J. 256 

WMAN First Baptist Church. _ Columbus. Ohio 286 

WMAP Utility Battery Service Boston. Pa. 246 

WMAQ Chicago Daily News - _ _ Chicago. ILL 448 

WMAV Alabama Polytechnic Institute _ .Auburn. Ala. 250 

WMAW Wahpeton Electric Co Wahpeton. N. D. 254 

WMAY Kingshighway Presbyterian Church. _ —St. Louis, Mo. 280 

WMAZ Mercer University _ __ - .Macon. Ga. 268 

WMC "Commercial Appeal" (Commercial Publishing Co. (....Memphis. Tenn. 500 

WMH Precision Equipment Co Cincinnati. Ohio 248 

WMU Doubleday-Hill Electric Co - —Washington. D. C. 261 

WNAC Shepard Stores ...- _ ._ Boston. Mass. 278 

WNAD University of Oklahoma _ Norman. Okla. 360 

WNAL R. J. RockweLL Omaha, Nebr. 242 

WNAM Ideal Apparatus Co _ _ Evansville. Ind. 360 

WNAN Syracuse Radio Telephone Co — _ Syracuse, N. Y. 286 

WNAP Wittenberg College „ _ Springfield, Ohio 231 

WNAQ Charleston Radio Electric Co _ Charleston, S. C. 360 

WNAR C. C. Rhodes _ _ _ ...Butler. Mo. 231 

WNAS Texas Radio Corp. & Austin Statesman. _ Austin. Texas 360 

WNAT Lennig Brothers Co. (Frederick Lennig) —Philadelphia, Pa. 360 

WNAV Peoples Telephone & Telegraph Co Knoxville. Tenn. 236 

WNAW Peninsular Radio Club (Henry Kunzmann).... Fort Monroe, Va. 360 

WNAX Dakota Radio Apparatus Co .Yankton, S. Dak. 244 

WNJ Shotton Radio Manufacturing Co _ _ Albany, N. Y. 360 

WOAA Dr. Walter Hardy. _ _ .Ardmore, Okla. 360 

WOAC Maus Radio Co _ _ Lima. Ohio 266 

WOAD Friday Battery & Electric Corp _ _ _... Sigourney. Iowa 360 

WOAE Midland College _ _ _ Fremont. Nebr. 360 

WOAF Tyler Commercial College _ _ _ Tyler. Texas 360 

WOAG Apollo Theater (Belvidere Amusement Co.) Belvidere. 111. 224 

WOAH Palmetto Radio Corp _ Charleston. S. C. 360 

WOAI Southern Equipment Co _ _ San Antonio. Texas 385 

WOAL William E. Woods... „ _ Webster Groves. Mo. 229 

WOAN Vaughn Conservatory of Music (James D. Vaughn) 

Lawreneeburg, Tenn. 360 

WOAO Lyradlon Mfg. Co _ _ _ Mishawaka, Ind. 360 

WOAP Kalamazoo College ...- _ Kalamazoo. Mich. 240 

WOAQ Portsmouth Klwanls Club... _ Portsmouth. Va. 360 

WOAR Henry P. Lundskow. _ _ Kenosha, Wis. 229 

WOAT Boyd M. Hamp .Wilmington. Del. 360 

WOAV Pennsylvania National Guard, 2d Battalion, 112th Infantry....ErIe, Pa. 242 

WOAW Woodmen of the World... _ _ _ Omaha, Nebr. 526 

WOAX Franklyn J. Wolff _ Trenton, N. J. 240 

WOC Palmer School of Chiropractic Davenport, Iowa 484 

WOI Iowa State College. _..- _ .Ames. Iowa 360 

WOK Pine Bluff Co _ —Pine Bluff. Ark. 360 

WOO John Wanamaker _ Philadelphia, Pa. 509 

WOQ Western Radio Co _ _ .Kansas City. Mo. 360 

WOR L. Bamberger & Co _ Newark. N. J. 405 

WOS Missouri State Marketing Bureau _ Jefferson City, Mo. 441 

WPAB Pennsylvania State College _ State College, Pa. 283 

WPAC Donaldson Radio Co Okmulgee. Okla. 360 

WPAH Wisconsin Department of Markets... Waupaca, Wis. 360 

WPAJ Doollttle Radio Corp _ .New Haven, Conn. 268 

WPAK North Dakota Agricultural College .Agricultural College, N. Dak. 360 

WPAL Superior Radio & Telephone Equipment Co _ Columbus, Ohio 286 

WPAM Auerbach & Guettel... _ ...Topeka. Kans. 360 

WPAP Theodore D. Phillips __ .Winchester. Kv. 360 

WPAQ General Sales & Engineering Co _ Frostburg. Md. 360 

WPAT St. Patricks CathedraL __ El Paso. Texas 360 

WPAU Concordia College _ _ _ _ Moorhead. Minn. 360 

WPAZ John R. Koch (Dr.) _ __ Charleston. W. Va. 273 

WPG Nusawg Poultry Farm _ ..New Lebanon. Ohio 234 

WQAA Horace A. Beale. Jr Parkersburg. Pa. 360 

WQAC E. B. Gish _ .Amarillo, Tex. 360 

WQAD Whltall Electric Co __ _ _ ...Waterbury, Conn. 242 

WQAE Moore Radio News Station (Edmund B. Moore) ....Springfield, Vt. 275 

WQAF Sandusky Register Sandusky. Ohio 240 

WQAH Brock -Anderson Electrical Engineering Co ....Lexington, Ky. 254 

WQAL Coles County Telephone & Telegraph Co Mattoon, III. 258 

WQAN Scranton Times _ _ Scranton. Pa. 280 

WQAO Calvary Baptist Church... _ .New York, N. Y 360 



54 



RADIO AGE— "THE MAGAZINE OF THE HOUR' 



Radio Construction Diagrams 



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RADIO AGE— "THE MAGAZINE OF THE HOUR" 



55 



Corrected List of U. S., Cuban and Canadian 
Broadcasting Stations 



WQAQ Abilene Daily Reporter (West Texas Kadio Co.) Abilene, Texas 

WQAS Prince-Walter Co. _ __ Lowell, Mass. 

WQAV Huntington & Guerry (Inc.) _.._ Greenville. S. C. 

WQAX Radio Equipment Co .. - .. Peoria, III. 

W R A A Rice Institute _ Houston, Texas 

WRAD Taylor Radio Shop (G. L. Taylor) _ _ _ Marion, Kans. 

WRAF The Radio Club (Inc.)...- _ -.._ -...Laporte, Ind. 

WRAH Stanley N. Read _ Providence, R. I. 

WRAL Northern States Power Co _ St. Croix Falls. Wis. 

WRAM Lombard College _ _...Galesburg, 111... 

WRAN Black Hawk Electrical Co _ _ .Waterloo. Iowa 

WRAO Radio Service Co _ - St. Louis. Mo. 

WRAV Antolch College _ _ Yellow Springs, Ohio 

WRAW Avenue Radio Shop (Horace D. Good) _ .Reading, Pa. 

WRAX Flaxon's Garage Gloucester City, N. J. 

WRAY Radio Sales Corp _ Scranton, Pa. 

WRAZ Radio Shop of Newark (Herman Lubinsky) .Newark. N. J. 

WRC Radio Corporation of America _ Washington, D. C. 

WRK Doron Bros. Electric Co... -...Hamilton. Ohio 

WRL Union College - Schenectady, N. Y. 

WRM University of Illinois _ Urbana. 111. 

WRR City of Dallas (police and fire signal department) Dallas. Texas 

WRW Tarrytown Radio Research Laboratory (Koenig Bros. ) ..Tarrytown, N. Y. 

WSAB Southeast Missouri State Teachers College Cape Girardeau. Mo. 

WSAC Clemson Agricultural College Clemson College, S. C. 

WSAD J. A. Foster Co _ Providence, R. I. 

WSAG City of St. Petersburg (Loren V. Davis) St. Petersburg, Pla. .. 

WSAH A. J. Leonard. Jr Chicago, 111. 

WSAI United States Playing Cards Co _ .Cincinnati. Ohio 

WSAJ Grove City College _ Grove City. Pa. 

WSAL Franklin Electric Co - _.._BrookvilIe. Ind. 

WSAN Allentown Radio Club __ - Allentovm, Pa. 

WSAR Doughty & Welch Electrical Co Fall River, Mass. 

WSAT Donohoo-Ware Hardware Co Plainview, Texas 

WSAW John J. Long. Jr _ _...Canandaigua, N. Y. 

WSAX Chicago Radio Laboratory _ - Chicago, 111. 



360 


WSAY 


266 


WSAZ 


258 


WSB 


360 


WSL 


360 


WSY 


248 


WTAB 


224 


WTAC 


231 


WTAF 


248 


WTAG 


.244 


WTAH 


236 


WTAJ 


360 


WTAL 


242 


WTAIH 


238 


WTAN 


268 


WTAP 


280 


WTAQ 


233 


WTAR 


469 


WTAS 


360 


WTAT 


360 


WTAU 


360 


WTAW 


360 


WTAX 


273 


WTAY 


360 


WTAZ 


360 


WTG 


261 


WWAB 


.244 


WWAC 


248 


WWAD 


309 


WWAE 


360 


WWAF 


246 


WWAO 


229 


WWI 


254 


WWJ 


268 


WWL 


275 


WYAM 


268 


WYAW 



Irving Austin (Port Chester Chamber of Commerce). .Port Chester, N. Y. 233 

Chas. Eleotrio Shop _ _ _ Pomeroy, Ohio 258 

Atlanta Journal _ Atlanta,, Ga. 429 

J. & M; Electric Co....- Utica. N. Y. 273 

Alabama Power Co „ -...Birmingham. Ala. 360 

Fall River Dally Herald Publishing Co Fall River, Mass. 248 

Perm Traffic Co _ _ Johnstown, Pa. 360 

Louis J. Gallo _ .New Orleans, La. 242 

Kern Music Co _ _ Providence, R. I. 258 

Carmen Ferro ..._ Belvidere, 111. 236 

The Radio Shop ..Portland, Me. 230 

Toledo Radio & Electric Co Toledo, Ohio 252 

Willard Storage Battery Co _ Cleveland, Ohio 390 

Omdorff Radio Shop _ __ _...Mattoon, 111. 240 

Cambridge Radio & Electric Co Cambridge. 111. 242 

S. H. Van Gorden & Son... _ Osseo, Wis. 220 

Reliance Electric Co ....Norfolk. Va. 280 

Charles E. Erbstein. ......Elgin. 111. 275 

Edison Electric Illuminating Co Boston, Mass. (portable) 244 

Ruegg Battery & Electric Co. Tecumseh, Nebr. 360 

Agricultural & Mechanical College of Texas ....College Station, Tex. 280 

Williams Hardware Co Streator, 111. 231 

Iodar-Oak Leaves Broadcasting Station Oak Park, 111. 220 

Thomas J. McGuire... Xa mbertville, N. J. 283 

Kansas State Agricultural College .Manhattan, Kans. 485 

Hoenig, Swern & Co. (John Rasmussen) Trenton, N. J. 220 

Sanger Bros. _ Waco. Texas 360 

Wright & Wright (Inc.) Philadelphia. Pa. 360 

Alamo Dance Hall, L. J. Crowley Joliet, 111. 227 

Galvin Radio Supply Co : Camden. N. J. 230 

Michigan College of Mines Houghton, Mich. 244 

Ford Motor Co .Dearborn, Mich. 273 

Detroit News (Evening News Assn.) .Detroit, Mich. 517 

Loyola University New Orleans, La. 260 

Electrelal Equipment Co _ Miami, Fla. 283 

Catholic University Washington. D. C. 236 



Canadian Stations 



CFAC Calgary Herald Calgary. Alberta. 430 

CFCA Star Pub. & Prtg. Co Toronto. Ontario. 400 

CFCF Marconi Wireless Teleg. Co. of Canada .Montreal, Quebec. 440 

CFCH Abltlbl Power & Paper Co Iroquois Falls, Ont. 400 

CFCJ La Cie de I/Evenemcnt _ _ Quebec, Quebec. 410 

CFCK Radio Supply Co Edmonton. Alberta. 410 

CFCL Contennial Methodist Church Victoria. British Col. 400 

CFCN W. W. Grant Radio (Ltd.) ..Calgary, Alberta 440 

CFCO Semmemhaack-Dickson (Ltd.) _ ..Bellevue, Quebec. 450 

CFCQ Radio Specialties (Ltd.) Vancouver. B. C. 450 

CFCR Laurentide Air Service ....Sudbury, Ont. 410 

CFCW The Radio Shop .-. Xondon. Ont. 420 

CFDC Sparks Co Nanaimo. B. C. 430 

CFQC The Electric Shop (Ltd.) Sasaltatoon. Sashatchewan. 400 

CFRC Queens University Kingston, Ontario 450 

CFUC University of Montreal Montreal. Quebec. 400 

CHAC Radio Engineers Halifax. Nova Scotia. 400 

CHBC Albertan Publishing Co Calgary. Alberta. 410 



430 


CHCD 


400 


CHCE 


440 


CHCL 


400 


CHYC 


410 


CJCA 


410 


CJGC 


400 


CJCD 


440 


CJCE 


450 


CJCI 


450 


CJCN 


410 


CJCX 


420 


CJSC 


430 


CKAC 


400 


CKCD 


450 


CKCE 


400 


CKCK 


400 


CKOC 


410 


CKY 



Canadian Wireless & Elec. Co „ Quebec, Quebec. 410 

Western Canada Radio Sup. (Ltd.).... _ Victoria. B. C. 400 

Vancouver Merchants Exchange Vancouver. B. C. 440 

Northern Electric Co Montreal, Quebec. 410 

Edmonton Journal JEdmonton, Alberta. 450 

London Free Press Prtg. Co London, Ont. 430 

T. Eaton Co '. Toronto. Ont. 410 

Sprott-Shaw Radio Co Vancouver. B. C. 420 

Maritime Radio Corp St. John, New Brunswick. 400 

Simons Agnew & Co Toronto. Ont. 410 

Percival Wesley Shackleton Olds. Alberta. 400 

Evening Telegram Toronto. Ont. 430 

La Presse Pub. Co Montreal, Quebec. 430 

Vancouver Dalley Province Vancouver. B. C. 410 

Canadian Independ. Telephone Co Toronto. Ont. 450 

Leader Pub. Co Regina. Saskatchewan. 420 

Wentworth Radio Supply Co Hamilton, Ont. 410 

Manitoba Telephone System Winnipeg. Manitoba. 450 



Cuban Stations 



PWX Cuban Telephone Co JHabana 400 

2DW Pedro Zayas - - - Habana 300 

2AB Alberto S. de Bustamante... - Habana 240 

20 K Mario Garcia Velez... - Habana 360 

2BY Frederick W. Borton Habana 260 

2CX Frederick W. Borton - Habana 320 

2EV Westinghouse Elec. Co. - Habana 220 

2TW Roberto E. Ramlres - Habana 230 

2HC Heraldo de Cuba _ Habana 275 

2LC Luis Casas - Habana 250 

2KD E. Sanchez de Fuentes - ..Habana 350 

2MN Fausto Simon - - ...Habana 270 

2MG Manuel G. Salas Habana 280 

2JD Raul Perez Falcon. - Habana 150 

2KP Alvara Daza Habana 200 

2HS Julio Power — Habana 180 



20L Oscar Collado _ _ _ .Habana 290 

2WW Amadeo Saenz _ JIabana 210 

5EV Leopoldo V. Figueroa _ Colon 360 

6KW Frank H. Jones Tuinucu 340 

6KJ Frank H. Jones _ Tuinucu 275 

6CX Antonio T. Figueroa _ Cienflegos 170 

6DW Eduardo Terry _ ...Cienflegos 225 

6BY Jose Ganduxe ...Cienfuegos 300 

6AZ Valentin Ullivarrl _ Cienfuegos 200 

6EV Josefa Alverax „ Caibarien 225 

8AZ Alfreda Brock-; _ Stgo. de Cuba 240 

8BY Alberto Ravelo _ Stgo. de Cuba 250 

8FU Andres Vinnet Stgo. de Cuba 225 

8DW Pedro C. Anduz Stego. de Cuba 275 

8EV Eduardo Mateos Stego. de Cuba 180 



Recognizing Voices 

Recently, a new announcer handled 
his first program through WEAF. On 
returning home he asked his mother 
whether she had heard the program 
during the afternoon. "Yes, " she re- 
sponded, but made no comment. A 
little surprised he asked how she had 
liked the announcing. Again a mono- 
syllabic answer. Finally he learned to 
his astonishment that his mother had 
not recognized his voice — so carefully 
had he applied the art of correct tone 
and enunciation for the microphone in 
acquiring a "radio" voice. 

On the other hand, not many days 
previous, another new announcer had 
been heard for the first time through 
WEAF for a few brief special announce- 
ments. Later in the evening, a friend 
telephoned a message of congratulation. 
He had not questioned for a moment but 
that the announcing voice was that of 
his friend, so perfect was its reproduction. 



Warship's Stunt 

The Battleship "Colorado" has just 
accomplished what radio engineers have 
said was impossible a few years ago. 
Her radio personnel has succeeded in 
receiving messages on five different wave 
lengths while her transmitter was send- 
ing dispatches across the continent on 
another wave length. 

This was accomplished by means of a 
special high-power tube transmitter. 




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56 



RADIO AGE— "THE MAGAZINE OF THE HOUR" 



ERLA BLUE PRINTS 

Erla Receivers out-distance other sets with an almost 
unbelievable volume and a naturalness that cannot be 
distinguished from the source of reception. 

This is the famous Erla Reflex Hook-up. Less than 
one year old — but has taken the entire nation by storm. 
Every listener-in raves about it and wants a set of his 
own immediately. 

So easy to construct that anyone who can handle a 
screw driver can build the set complete in a sur- 
prisingly short time — about 11-2 hours. Everything 
is so simple and easy. 

NO SOLDERING WHATEVER— ONLY A 
SCREW DRIVER NEEDED. 

The results from the Erla 3 tube is naturalness itself and can- 
not be improved upon. Actual size working diagrams make 
every thing simple and easy. Every piece of apparatus and 
every wire is pictured in its exact place — every article needed 
is listed on the diagrams. 

Diagrams sent same day your order is received. 
Send P. O. or Express Money Order or Bank draft 
or Bank Cashier's check. Do not send stamps or 
personal checks. 

Erla Hook-up Diagram Prices 

3 sheets for making 1 tube set 25c 
3 sheets for making 2 tube set 35c 
3 sheets for making 3 tube set 50c 

Frank D. Pearne 

Sole Distributor of Erla Diagrams for U. S. and Canada 
829 Waoeland Avenue, Chicago, III. 

Dealer; Write for Quantity Price* 



Farm Report 

Radio's first big bow to the agricul- 
tural interests of the nation was made 
recently when, in co-operation with the 
Stockman-Farmer Publishing Company, 
the Westinghouse Electric & Manufac- 
turing Company opened its third broad- 
casting studio in Pittsburgh. 

It was discovered that there was a 
general demand for market information 
and weather reports via radio, farmers 
realizing that such information would be 
of vital importance in the conducting 
of farm operations and particularly 
in the marketing of farm products. The 
first of July, 1923, witnessed the opening 
of a regular market reporting service 
which was conducted from the offices of 
the National Stockman and Farmer and 
broadcast by Station KDKA, the pio- 
neer in the farm field as elsewhere. 

The market reporting service developed 
so rapidly that it was soon found neces- 
sary to broadcast three market reports 
daily. As now constituted these market 
reports cover the primary activities of 
seven livestock markets, the principal 
grain and feed markets of the country, 
the New York Cotton market, the Bos- 
ton wool market, the fur market, pro- 
duce markets and numerous government 
reports on market and crop conditions. 
Two weather reports daily were added to 
the reporting activities of KDKA until 
the needs of practically every class of 
farmers in the nation were being filled 
by the broadcast market service. 

The need for a separate broadcasting 
studio soon arose and following the first 
few months of experiment the Stockman 
Farmer Publishing Company erected a 
well equipped studio in its building and 
have now perfected arrangements with 
the Westinghouse Company to give the 
required market report service. 

The interest of the United States De- 
partment of Agriculture was aroused by 
the success of KDKA's market reports 
and co-operation resulted, the govern- 
ment with its leased wire service helping 
the broadcasting station, so that market 
reports from the various centers of the 
country could be assembled and put on 
the air. In addition, the United States 
Weather Bureau with the co-operation 
of the Western Union Telegraph Com- 
pany, gave special service on the night 
weather report so that this report is now 
broadcast from KDKA just a half-hour 
after being issued at Washington, D. C 

Since the inception of the market re- 
porting service in 1923, the National 
Stockman and Farmer has heard from 
all but nine far western states while the 
reports have been heard in Canada, Cuba, 
Jamaica, the Virgin Islands, South 
America and England. 



Don't Fail to renew your 
subscription ? 



long distance 
clear signals! 




You too can get distant stations clearly if you use Howard 

Rheostats. 

The point of oscillation of a tube is narrow, you cannot get 

the best results unless you are able to control this point. 

Howard micrometer Rheostat does this, easily, simply — surely. 

Smooth, positive contact is just one of the reasons. 

Ask your dealer — he knows and will be glad to show you. 



No. 1004 




Multi Terminal Receiver 
Plug, instantaneous con- 
nection for as many as 
six pairs of standard re- 
ceiver tips .....$2.00 

Paid. Aug. 28, 1923 



Jobbers Write for Discounts 

HOWARD 

Howard Radio Co., Inc., 

4248 North Western Ave., Dept. A, Chicago 




No. 1001 

b l / 2 Ohm Rheostat $1.10 
25 Ohm Rheostat 1.10 

40 Ohm Rheostat 1.10 

60 Ohm Rheostat 1.10 

[ [Patd\870,042 ._*, 



No. 1003 

200 Ohm Potentio- 
meter.. ..$1.50 

400 Ohm Potentio- 
meter 2.00 

Patd. 870,042 



No. 1002 

6^0hm Micrometer 

Rheostat... $1.50 

25 Ohm Micrometer 

Rheostat 1.50 

40 Ohm Micrometer 

Rheostat 1.50 

60 Ohm Micrometer 

Rheostat' 1.50 

Patd. July 10;j923 



Earn'5»to s 202?aDay 

in RADIO 



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L " JS'o matter if you know nothing about Radio now, you can quickly 
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36q Marine of the 

APRIL 

1924 





This 
Number 



An efficient Super -Hetero- 
dyne. 

Methods of radio frequency 
amplification. 

What receiving set do I want? 

New Reinartz circuit with 
picture diagram. 

Another Rathbun hook-up. 

Complete corrected list of 
stations. 

Pick-ups and hook-ups by 
our readers. 

Many illustrations. 



i&m 



Let Our Hook-ups Be your Guide 




ono45 

REGISTERED 



KIT 



All the Parts Needed to Build a Circuit That Brings 

Them in From Coast-to-Coast on ONE TUBE — 

High Grade Equipment of Proven Quality — Every 

Part Tested in Our Laboratory 



The Long 45 Circuit has startled 
the radio world with its efficient 
simplicity. Performances that 
were impossible with the larger 
and much more expensive sets 
were "all in the day's work" with 
this remarkable combination. 
Easy to assemble. Easy to op- 
erate. Easy to add to. The Long 
45 starts you right in radio and 
will surprise you every night with 
programs from distant stations 
you've never heard before. In- 
structions and blue print so plain 
that anyone can build the set. 

Your dealer has or can get one 
for you. 



[;;•■ ; - ■■■"■■ ..--■■ -•■■ ■ ■ - . '. IT . 



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[MARCO ME yetfc. 

¥i ■ a ■ * iO. - , "i ■ ■ .^i 



f.col 



The "Long 45" Kit Contains: 



1 Long 45 Tuner 

1 Long 45 Cartridge 
Rheostat 

1 Long 45 23-Plate Va- 
riable Condenser 

1 Bakelite Socket 

1 C. R. L. Adjustable 
Grid Leak and Conden- 
ser 

1 Long 45 Blue Print 



1 35-Turn Branston 

Honeycomb Coil and 

Mounting 
1 Carter No. 3 Switch 
1 Carter Jack 
1 7x12 Celoron Drilled 

Panel 
1 Base Board 
5 Binding Posts 

Bus Bar 



Price. S2252 



MARCO MEYER & CO. 



1319 Michigan Avenue 



RADIO DIVISION RA 



Chicago 



RADIO AGE for April, 1924 



The Magazine of the flour 




, - 



Licensed under Armstrong- U.S. Patent No. 1,113.149 



Eleven Degrees from the North Pole 




Ice — endless miles of ice, 
as far as the eye can see. 
And frozen fast in the ice, 
amid the deadly stillness 
and the unearthly lights 
of the Arctic, a staunch 
little eighty-nine foot 
schooner! But Donald B. 
MacMillan and his band 
of brave explorers are not 
alone tonight. 

Under their ice-bound hatches they listen eagerly 
to the news of the outside world, broadcast to them 
from the Zenith- Edgewater Beach Hotel Broadcasting 
Station, Chicago — to violins in Newark, Schenectady, 
Los Angeles — to singers in Atlanta — to a lively orchestra 
in Honolulu. 

Stations in all these cities — and in several hundred 
others — they have readily tuned in; yet the Bowdoin 
tonight is only eleven degrees from the North Pole ! 

Out of all the radio sets on the market, Dr. MacMillan 
selected the Zenith exclusively — because of its flawless 
construction, its unusual selectivity, its dependability 
and its tremendous REACH. 

And you can do all that Dr. MacMillan does, and 
more, with either of the two new models described 
at the right. Their moderate price brings them easily 
within your reach. Write today for full particulars. 

Zenith Radio Corporation 

McCORMICK BUILDING, CHICAGO I Address 

Always Mention RADIO AGE When Writing to Advertisers 



Model 3R The new Zenith 3I * "Long- Distance" 
iriuuct *JA\ Receiver-Amplifier combines a spe- 
cially designed distortionless three-stage amplifier with the 
new and different Zenith three-circuit regenerative tuner. 
Fine vernier adjustments — in connection with the 
unique Zenith aperiodic or non-resonant "selector" primary 
circuit — make possible extreme selectivity. 

2,000 to 3,000 Miles With Any 
Loud -Speaker 

The new Zenith 3R has broken all records, even those set 
by its famous predecessors of the Zenith line. Satisfactory 
reception over distances of 2,000 to 3,000 miles, and over, 
is readily accomplished in full volume, using any ordinary 
load-speaker. No special skill is required. 

The Zenith is the only set built which is capable of being 
used with all present-day tubes as well as with any tubes that 
may be brought out in the future. The Model 3R is compact, 
graceful in line, and built in a highly finished mahogany 
cabinet 



$160 



h/lnrSfJ 4/? The new Zenith 4R "Long-Distance" Receiver- 
TT1Y Amplifier comprises a complete three-circuit 
regenerative receiver of the feed-back type. It employs the new 
Zenith regenerative circuit in combination with an audion detector 
and three-stage audio-frequency amplifier, all in one cabinet. 

Because of the unique Zenith "selector," unusual selectivity is 
accomplished without complication of adjustment. 

The Zenith 4R may be connected directly to any loud-speaker 
without the use of other amplification for full phonograph volume, 
and reception may be satisfactorily accomplished over (hn C 
distances of more than 2,000 miles CpOO 



ZENITH RADIO CORPORATION, 

Dept.S , 328 South Michigan Avenue, Chicago, Illinois 

Gentlemen : 

Please send me illustrated literature on Zenith Radio. 



Mame. 



RADIO AGE for April, 1924 



The Magazine of the Hour 



RADIO AGE 

The Magazine of the Hoar 

Established March. 1922 



Volume 3 



APRIL, 1924 



Number 4 



CONTENTS 



Page 
An Efficient Super-Heterodyne Receiver. 5 
By Arthur B. McCullah. 

Selecting the Right Receiver 11 

By Frank D. Pearne. 

A Ten Dollar Receiver 13 

By J. B. Rathbun. 

Anti Body Capacity Hookups 15 

By Roscoe Bundy. 

Radio Frequency Amplification 17 

By P. E. Edleman. 

Reflexino" the Three Circuit Tuner 19 

By Brainard Foote. 

Pickups and Hookups 21 

By Our Readers. 

Radiotorials 28 

New Radio Bill 29 

By Fredrick A. Smith. 

What the Broadcasters are Doing 31 

Data Sheets 34 

With the Manufacturers 40 

Questions and Answers 42 

Corrected List of Broadcasting- Stations. .48 



Radio Age is published monthly by 
• RADIO AGE, Inc. 



Editorial and Publication Offices, Boyce Building, 
500 N. Dearborn St., Chicago 



Frederick Smith, Editor 
Frank D. Pearne, Technical Editor 
M. B. Smith, Business Manager 
Louis L. Levy, Circulation Director 

Western Advertising Representatives 
BRUNS & MACDONALD 

First National Bank Building, Chicago 
Eastern Representatives 

E. V. HEVEY h COMPANY 

17 West 42nd Street, New York City 

Telephone, Longacre 1698 



Advertising forms close on the 1 5 th of the month 

preceding date of issue 

Applicants for membership in A. B. C 

Issued monthly; Vol. 3, No. 4 Subscription price $2.50 a year. 

Entered as second-class matter April 8, 1922. at the post office at Chicago, 

Illinois* under the act oi March 3, 1S79. 



Copyright, 1924, by RADIO AGE, Inc. 



A Chat With 
the Editor 

THERE are two departments 
in this issue of RADIO AGE 
which demonstrate what we 
have said repeatedly. That is: This 
is essentially a readers' magazine. 
In the section devoted to letters 
from readers on sets they have 
built and results they have obtained 
there is a generous store of useful 
information for other readers. We 
want all readers to understand that 
we are interested in these letters, 
especially the ones suggesting new 
hook-ups and new kinks. 

Also in the columns in which 
appear the letters from readers who 
tell us why they read RADIO 
AGE there will be found some in- 
formation that will interest the 
craft generally. Those readers who 
write to express approval of cer- 
tain methods of presenting radio 
subjects may not find it hard to 
believe that so many other fans are 
pleased with RADIO AGE draw- 
ings and articles and are buying 
so many of our magazines that we 
have been forced to put the print 
order up to ■; 0,000. That was the 
March figure. The press run for 
this issue cannot be definitely es- 
timated as orders from wholesale 
distributors are still coming in as 
we are preparing to put the plates 
on the press. 

While we are discussing circula- 
tion we may as well call attention 
to the fact that we are applicants 
for membership in the Audit Bu- 
reau of Circulations, which fur- 
nishes verified figures on total 
number of magazines printed, dis- 
tributed and sold. 

We notice that Canadian readers 
are increasing in number with 
gratifying- rapidity. Many of them 
are writing us just the sort of con- 
structive letters we like to get. 

For all of you we want to sug- 
gest that you do not permit the 
Spring days to lure you away from 
attention to several good features 
that we know are in store for you 
in early issues. 

—Editor, RADIO AGE 



THE AIR IS FULL OF THINGS YOU SHOULDN'T MISS'' 




Why Big Cells Count in Radio "B" Batteries 



THIS handsome metal case Eveready 
"B" Battery No. 766 costs only two- 
thirds more than the smallest Eveready 
"B" Battery, but it contains seven times 
the electricity! This makes the No. 766 
over four times as economical as its baby 
brother. That is why most people buy it. 

Its fifteen large cells give izVz volts of 
strong, steady energy day after day. 
Cells that pour out power the moment 
you turn on your tubes. 
Cells that rest well when 
idle, renewing their vigor 
for your next demands. 

No cells have a bluer- 
blooded ancestry than 
these. They are the prod- 
uct of thirty years of dry 
battery research and 
development of the 




Eveready "B" Battery No. 766 

22 Vz volts. Six Fahnestock Spring Clip 
Terminals, giving variable voltage from 
i6!4 to 22 Vi volts, in I'/i-volt steps. 
Length, 6 3 A in.; width, 4!^ in.; height, 
3 3/16 in. Weight, 5 lbs. 



world's foremost electro-chemical 
la boratories . We think that No . 766 is the 
handsomest battery ever made. But that 
is a matter of opinion. It is a matter of 
engineering record, however, that this 
great standard "B" Battery has proved 
itself as perfect in performance as we are 
convinced it is superfine in appearance. 

The 45-volt Eveready No. 767 contains 
the same large powerful cells as the No. 
766. For maximum "B - " 
Battery economy, there' 
fore, buy the 22 1 /i-volt 
Eveready No. 766 or the 
45-volt Eveready No. 767, 
as you prefer. Here is the 
"B 11 Battery at its best. 



National Carbon Company, Inc. 

Headquarters for Radio Battery Information 

New York San Francisco 

Canadian National Carbon Company, Limited 
factory end Offices: Toronto, Ontario 




If you have any radio battery problem, write to G. C. Furness, Manager, Radio Division, 
National Carbon Company, Inc., 202 Orton Street, Long Island City, N, Y. Inform- 
ative and money-saving booklets on "A," "B" and "C" Batteries sent free on request. 



No. 764 

The Space 
Saver 
Vertical 
22 !4 -volt 

"B" Battery 



Eveready 

Radio "A" 

Dry Cell 

Specially 

manufactured 

for use with 

dry cell 

tubes 



Radio Batteries 

—(hey last longer 

W~ -7-71 ^ *» 



No. 767 

B" Battery, 45 volu 

Variable taps 
Fahnestock Clips 

Always Mention RADIO AGE When Writing to Advertisers 



"C" Battery 

Clarifies tone and 

increases "B" 

Battery life 



RADIO AGE for April, 1924 



The Magazine of tlte Hour 




r 



RADIO AGE for April, 1924 

H I I ES I ~I BE 



The Ma-gazine of the Hour 5 

^pi p i nr: m r= i nr 





<^fe Magazine g^/fte Hour 



"i 



M. B. Smith 

Business Manager 



A Monthly Publication 

Devoted to Practical 

Radio 



Frederick A. Smith 

Editor 



HJE3E 



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DOE 



3HC 



]BE 



SIDE 



3QE 



3BE 



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3HG= 



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3EE 



J 



An Efficient Super-Heterodyne 



D ELVERS in physical and scientific 
research have established enviable 
reputation for their zeal in push- 
ing ahead beyond the confines of their 
fields. Obstacles have been surmounted 
by patient toil; perfection has been 
sought and surpassed and sought again, 
and the finished task has been only a task 
begun. In the field of radio research we 
have been zealous enough and the world is 
witness to the wonders accomplished; yet 
it is a fact that our search for an in- 
strument that would prove a practical re- 
ceiver for the layman, we have attempted 
to single out the simplest type of set with- 
out regard to the fundamentals and sen- 
sitivity and quality, and have shied away 
from the greatest and most efficient of all 
systems — the super-heterodyne, because 
of its supposed difficulties in construction 
and control. 

Contrary to general belief, the super- 
heterodyne is a simple and easily con- 
trolled receiver, if built right. Tuning is 
much more easily done than on a one-tube 
receiver. This is because of the fact that 
the signal of a transmitting station is made 
to fit the set rather than the set made to 
fit the signal, the procedure followed out 
in small sets. 

It is possible to construct a super- 
heterodyne in which the control centers 
around two dials, the tuner and the 
heterodyne, or oscillator. In constructing 
a set of this type, one must adhere closely 
to the constructional details that follow. 
If this is done, no difficulty will be expe- 
rienced in building a really super-set, and 
one that will meet all of the expectations 
as to selectivity, distance, and quality 
of reproduction. 

Theory of Amplification 

Before going into the explanation of 
the actual construction of the receiver, it 
might be well to review the theory of 
operation. Let us first, as a matter of 
primary importance, consider the common 
short wave receiver with both radio and 
audio frequency amplification. 

It will be found that one stage of audio 
frequency amplification will give by far 
more amplification than two stages of 
radio frequency amplification. This is due 
to three factors, viz.: (1) the alternating 



By ARTHUR B. McCULLAH 

current losses are much greater at high 
frequencies due to the increase of eddy 
currents and dielectric absorption (loss- 
es); (2) leakage through stray capacity is 
greater at high frequencies than at low 
frequencies; (3) it is more difficult to con- 
trol tube oscillations at high frequencies 
than at low frequencies. These three fac- 
tors show concisely that the low frequen- 
cies can be amplified best, and the logical 
thing to do therefore would be to amplify 
them at the low frequencies (long waves) 
instead of the high frequencies where all 
these losses have to be contended with. 

Unfortunately, however, broadcasting 
is done on extremely high frequencies 
(short waves) and in order to obtain the 
desired results, it is necessary to lower the 
frequency so that it may be amplified 
more efficiently. Although this was ac- 
complished during the war by Major Arm- 
strong with his super-heterodyne receiver, 



radio designers have shunned this system 
as being impracticable for the layman. 
The very term "super-heterodyne" con- 
jured all sorts of difficulties, and designers 
left the construction and use of the sys- 
tem to only a genius like Mr. Armstrong 
himself. 

Three Units 

Instead of building the super on one 
large panel of large dimensions, we shall 
build it in a more serviceable size. In 
doing this, we must think of the set as 
being in three component parts. These 
units will be referred to as follows: Unit 
one, wave-changer; Unit two, the long 
wave amplifier and detector; Unit three, 
the audio frequency amplifier. Reference 
to Figure 00 will show the subdivision of 
these units, illustrating the heterodyne or 
wave-changer mounted on the main con- 
trol panel, the intermediate amplifiers and 




Figure 2 

CONSOLE ARRANGEMENT 

A front elevation of the beautiful console type of super-heterodyne receiver, its 
design making it a desirable furnishing for the most elaborate drawing room. The 
music and programs from broadcast stations issue from the loud speaker with! 
more volume than can be obtained from a phonograph, and with clarity that has 
not been excelled. The switch-knob directly to the right of the loud speaker 
enables the operator to control the volume of the signals, from the smoothest and 
softest intensity, to a deafening roar. The set when not in use presents the 
appearance of a phonograph. 



RADIO AGE for April, 1924 



The Magazine of the Hour 



their controls on a sub-panel, and the 
audio frequency unit in another section 
of the receiver. 

Why Units Are Separated 
By doing this, two things may be ac- 
complished. The units may be arranged 
attractively and artistically in such a man- 
ner that it will not be necessary to have 
a specially constructed piece of furniture 
in which to house it. The wiring will be 
short and direct in the units themselves, 
and it enables the constructor to exercise 
his own taste as to the location of the 
units, so long as the connecting leads are 
kept within the bounds of reason. 

Construction 

The coupler and oscillator coils are 
both wound on the same size tube. The 
coupler is wound on a bakelite tube 2J4 
inches in diameter, which should be 3 
inches in length. Two coils are wound, 
the secondary being wound first, which 
consists of 60 turns of D. C. G. S. wire. 
A layer of empire cloth is then wound 
over the one end of this coil, and directly 



over the empire cloth, another coil, form- 
ing the primary of the coupler is wound. 
This consists of 4 turns of the same size 
wire. The construction of this coupler is 
illustrated in Figure 00, and is the medium 
used to couple the receiver to the an- 
tenna, which can be of the ordinary out- 
door type, not over 80 feet overall length, 
including leadin. 

The Oscillator 

On another piece of tubing, the same 
size as before mentioned the oscillator 
coils are wound. Starting at the left end, 
wind 27 turns of the No. 20 D. C. G. S. 
wire, and fasten the end. One-eighth of 
an inch to the right, start another coil and 
wind 36 turns of the same size wire. The 
first coil mentioned is L3 and the latter 
bears the term L4, and together, they 
form the oscillator unit of the receiver. 

The tubing holding these coils may be 
mounted on pillars or other suitable 
mountings; they are a matter of appear- 
ance only. The oscillator coil must be 
mounted near the oscillator bulb and con- 
denser, while the secondary coil may be 



mounted a good distance away from the 
secondary condenser if desired. (Note: 
The oscillator may be mounted in the 
same manner as described in the super- 
heterodyne article of the March, 1924, 
issue of RADIO AGE to advantage, by 
omitting the smaller tubing and using the 
larger outside one only. This form of 
mounting is exceedingly effective. While 
it is possible to use long leads on the sec- 
ondary circuit, be reasonable, and make 
them as short as you conveniently can. It 
is a tuned circuit, and you can add ma- 
terially to the effectiveness of the receiver 
by keeping the resistance of this circuit 
as low as possible. — Tech. Ed.) 

The design of the front panel is left to 
the builder's taste. The only thing that 
is necessary to have on the main operating 
panel is the secondary and oscillator con- 
densers, and a filament- control switch, 
which enables the operator to turn the 
filament current off at will without having 
to remove one of the battery leads from 
the battery. 

Follow out the detail and wiring dia- 
gram of the oscillator very closely, and 




Figure 1 
HETERODYNE CRAFTSMANSHIP 
Arthur B. McCullah, a student of Lane Technical High School of Chicago, operating the ten-tube super-heterodyne 
receiver designed and built by himself. The set is a rare example of careful engineering and painstaking workmanship. 
Stations from every part of the country are received on the loud speaker with unbelievable consistency and volume. The 
photo shows Mr. McCullah making some preliminary adjustments with the receiver, before plugging in on the loud speaker, 
which is operated by two stages of audio amplification, consisting of one cascade amplifier and one push-pull type. Opera- 
tion of this receiver is comparatively simple, the only two controls used being the two shown with the white dials, once, 
the set is adjusted to proper operating conditions. The stations come in on two places on the oscillator condenser dial, and 
the tuning is so sharp that care must be taken not to pass over the spot where the signal is received. 



RADIO AGE for April, 1924 



The Magazine of the Hour 



"* - 



c 3 



C2 



OC 



OL 







#a sc 



C? D 







SNAPPY RADIO ENGINEERING 
The back panel view of the oscillator-radio frequency-detector panel of the super-heterodyne receiver. The legends refer 
to the following units of the receiver: C5 condenser, used to tune the radio frequency transformer T4; C4, used to tune T3; 
C3 tunes T2, and C2 tunes Tl. The primary of the long wave coils LWC is tuned by fixed condensers hidden behind the 
mounting panel, and the secondary is tuned with condenser CI. OC is the oscillator condenser, OL the oscillator coils, and 
O the generating tube. M is the frequency changer or modulator tube, and D is the detector. Rl, 2, 3 and 4 are the tubes 
furnishing the radio frequency amplification, while P is the potentiometer used to bias them. SC, the secondary con- 
denser, used for tuning in the signals from the loop or other antenna, and the oscillator condenser OC are the only controls 
used for tuning, once the set is adjusted. The output from the detector tube D is transferred to an audio frequency ampli- 
fier shown in Figure 5. The bakelite strip AC is the angle changer, which changes the angles of all the coils simultaneously. 
All the controls which require preliminary adjustment are mounted on a separate panel immediately back of the operating 
panel, which contains only the secondary and oscillator condensers, a meter and a filament control switch. 



no trouble in making the heterodyne unit 
oscillate will be experienced. 

Intermediate Amplifier 

The long wave (low frequency) ampli- 
fier is of the tuned type which gives great- 
er amplification per stage than any other 
known type. The construction of such 
an amplifier is very simple. 

Ten Giblin-Remler inductance coils are 
mounted on five pieces of bakelite tubing, 
two coils on a tubing, which is in turn 
mounted on two strips of bakelite which, 
when pulled back and forth, change the 
angje of the coils simultaneously to a 
common base. This feature alone adds 
to the general efficiency of the set due to 
the fact that the inductive coupling be- 
tween the air core transformers is mini- 
mized. 

Two strips of bakelite -)4x34xj4 inch 
are used to mount the coils.; In. drilling 
the hole through the strips it is neces- 
sary to place one strip on top of the other 
that the holes will be the same distance 
apart. One-inch 6-32 brass bolts are put 



through the holes in the strip, and three 
nuts are put on the bolt. The lower one 
is tightened down while the others are 
left near the top of the bolt and are 
clamped through a hole in the tubing as 
shown in Figure 00. 

From the list of materials needed it can 
be seen that six (6) 400 turn Giblin- 
Remler inductance coils are needed; four 
(4) 100 turn coils of the same make so 
that the coils will all have the same inside 
diameter. 

These ten coils are arranged into five 
air core transformers. Transformer No. 
1 has two of the 400 turn inductance coils 
mounted on a piece of bakelite tubing 
just large enough to slide into the small 
hole in the inductance coil, and 5 inches 
long. These -two 400 turn coils are placed 
on the extreme end of the 5-inch tube. 
Transformers 2, 3, 4 and 5 are placed with 
one 400 turn coil and a 100 turn coil on 
each tube placed in the center, ]/% inch 
apart. The accompanying photograph 
illustrates the method of mounting them 
clearly. The opposite ends of the tubing 



are anchored to the mounting board. 
When the one strip is moved it changes 
the angles of all of the coils, and the 
coupling can be varied, until the lowest 
possible interaction is obtained. 

The secondary of the five air core trans- 
formers are tuned with .0005 MF variable 
condensers and are mounted on a sub- 
panel. This is done so that after the con- 
densers are once adjusted they will be out 
of reach and not tempt one to turn them. 
This sub-panel is 3K , x32x%6, has also a 
potentiometer mounted between con- 
denser 3 and 4. After the condensers and 
potentiometer is mounted on the sub-pa n el 
this whole sub-panel is mounted on three 
brass uprights -}i inch square and 7 inches 
long. Their uses are illustrated in the 
accompanying photos. 

Tubes 

The four radio frequency tube sockets 
are placed between their respective trans- 
formers. This will make the grid and 
plate leads shorter and prevent the leads 
from running parallel. The tubes should 



RADIO AGE for April, 1924 



The Magazine of the Hour 






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RADIO AGE for April, 1924 



The Magazine of the Hour 




ARMSTRONG'S SUPER-HETERODYNE 

The back-panel and interior of the cabinet of Maj. E. H. Armstrong's super- 
heterodyne six-tube set, with which he picks up London. It will be observed that 
the tubes are on the front of the panel. See other photograph. 



be UV 201 A amplifying type with the ex- 
ception of the oscillator, detector and 
audio frequency amplifiers, which should 
be WE 216 A, UV 200 and WE 216 A re- 
spectively. 

On the first radio frequency long wave 
coils designated LWC, the coil towards 
the front is called the input coil. This 
input coil is shunted with a .0003 fixed 
condenser of the mica type. The coil to- 
wards the back of the set is connected to 
the first variable condenser on the sub- 
panel. If the baseboard is not long enough 
the detector tube and socket may be 
mounted in front of the fifth condenser. 
It might be well to state here that the 
grid leak must be of a very low value 
(about a 1 or ?4 megohm leak will do), to 
prevent the detector tube from disturbing. 

Audio Frequency Unit 
The audio frequency amplifying unit is 
mounted on the same base with the other 
two units or it may be mounted on another 
small base near the loud speaker. The 
audio frequency amplifier is a two-stage 
the first stage being a common cascade 
type while the second stage is of the mul- 
tiple or push-pull type. These are noth- 
ing out of the ordinary about this 
amplifier, and it is not necessary to dwell 
on the subject of its construction. (Full 
details were published in the January, 
1924, issue on the Push-Pull amplifier. 
Tech. Ed.) 



Tuning Intermediate Unit 

The tuning of the long wave radio fre- 
quency amplifier is very easy. A small 
buzzer that gives an 800-cycle note is best 
for this job. It is connected in series with 
an ordinary dry cell, and connected across 
the input coil. The note of the buzzer is 
then adjusted so as to give a clear note, 
and to make the least sparking possible. 
Connect a crystal detector and headset 
across the secondary or the condenser of 
the other 400 turn LWC. The first con- 
denser is varied until the buzz is heard at 
its loudest point. Turn on the current 
of the first tube (first radio frequency 
amplifier) and connect the headset and 
crystal detector across the terminals of 
the second condenser. Proceed in the 
same manner by tuning the condenser un- 
til the loudest signal from the buzzer is 
heard; though this time it will be louder, 
due to the fact that it is amplified by the 
first RF tube. This process is continued 
until the entire intermediate amplifier is 
tuned. 

Tuning the Set 

Your receiver is now ready for use. 
Upon tuning in, one will find that there 
will be two points on the heterodyne dial 
where the stations come in if everything 
is adjusted properly. If, however, there 
are more than two points, the amplifier 
should be retuned. 



List of Materials 

2 Dials. 

1 Voltmeter, 0-10, Jewell. 

5 .0005 variable condensers. 
1 .0005 variable condenser. 

1 .001 variable condenser. 

6 400-turn inductance coils. 

4 100-turn inductance coils. 

1 Potentiometer. 

3 .002 fixed condensers, mica type. 

5 pieces of bakelite, 2 inches in diam- 

eter, 5 inches long. 

2 pieces of bakelite, 3 inches in diam- 

ameter, 4 inches long 

1 }4-pound S p 00 i d q q s 
10 Sockets. 

2 %x34x^4-inch bakelite strip. 

1 3y2x32x l /4-mch bakelite strip. 
1 8xl8xJ4-inch front panel, bakelite. 
1 .00025 grid condenser. 
1 1 -megohm grid leak. 

3 'Brass rods, Y%~s.l inches. 
1 Carter on-off switch. 

1 Audio frequency transformer (4 to 1). 
1 Audio frequency transformer, push- 
pull. 

1 Loud speaker unit. 

2 Rheostats, power type, 3 ohms. 

6 201A or 301A tubes. 

4 216A tubes. 

Editor's Note: Only the very highest 
quality equipment should be selected in 
making the set described in the foregoing. 



10 



RADIO AGE for April, 1924 



The Magazine of the Hour 




RADIO AGE for April, 1924 



The Magazine of the Hour 



11 



Selecting the Right Receiver 

By FRANK D. PEARNE 



THE question of selecting the proper 
radio receiver to suit his particular 
case, is more serious to the begin- 
ner than one would at first suppose. So 
many things enter into this problem that 
it is no wonder that the poor fellow makes 
an appeal for guidance in this matter, to 
those who have gone before and have 
learned by hard and expensive experience, 
what the uninitiated are up against when 
they blindly grope about in the purchase 
of their first radio set. 

The number of radio enthusiasts is 
growing rapidly, so rapidly, in fact, that 
the manufacturers of radio sets and parts 
cannot keep the pace, some of them being 
several thousand behind in their orders 
for sets, and this, in the face of day and 
night operation of their factories, proves 
beyond a doubt that the interest in radio 
is increasing so fast that it is destined to 
become one of the greatest industries in 
the history of our country. 

But what of the poor beginner? On 
every side he hears about this and that 
wonderful set. He hears about radio fre- 
quency, audio frequency, detectors, con- 
densers, all new to him, and he starts out 
to see what he can get for a reasonable 
expenditure of good cold cash that will 
put him in this ever increasing multitude 
of broadcast listeners. 

Buyer Is Bewildered 
Here is where his real trouble begins. 
Every store he enters will show him some- 
thing different, all being the best that 



je&AL 



AERIAL 




*D 



CRYSTAL 



CONDENSER 
•OOOS" ■ 



CONDENSER 

■0002s 




£•(•) BINDING POST 
GROUND 

FIGURE 1 
A diagram of the Long Distance Crystal receiver, which is a desirable receiver for 
the new beginner in the radio pastime. : The set is easily constructed, requires little or 
no knowledge of radio, and gives surprising results. The binding posts, A-l and A-2, 
are used as part of the tuning system, the A-2 post being used for the lower waves and 
the A-l for the higher. This applies especially where -the antenna used is a long one. 



money can buy. His eyes will suddenly 
be opened to the fact that there are more 
different types of radio receivers than he 




<&?£ 



6£0OAia 



FIGURE 2 
A diagram of the type of set which would make a desirable receiver for one who is 
making his first steps in the art of building a tube receiver. This set was described in 
detail in the October, 1923, issue of RADIO AGE, together with instructions for the 
conversion of crystal receivers into tube units. It has a consistent long distance range, 
and has often accomplished 2,000-mile receptions. 



ever dreamed of and the farther he goes, 
the more discouraging it looks to him. If 
he does find something which looks inter- 
esting, some fellow is sure to suggest that 
he is all wrong and point out to him the 
numerous defects in this particular set 
and will probably rave about his own won- 
derful set, finally convincing the would-be 
purchaser that he has not yet discovered 
what he wants. 

First of all one should understand that 
hardly any two fans have the same ex- 
perience with the same set. An outfit 
which will work very well in one location 
with a certain aerial, will act entirely dif- 
ferent when used in a different location 
with a different aerial. This fact probably 
is responsible for so many differences of 
opinion expressed by those who have had 
experience. 

Then, too, much discontent is caused by 
the fan who exaggerates the number of 
long distance stations which he has heard 
and the beginner, after installing a fairly 
good set, is much disappointed when he 
doesn't get these results. As a matter of 
fact it is very hard to say just what any- 
one can do with a certain set, until it has 
been proven by actual practice. As stated 
before, the selection of the proper set is 
a question which is really hard for even 
an expert to answer, for the reason that 
location has much to do with the results 
obtained. 

Aside from location, there are many 
other points to consider. It is a well 
known fact that about 50 per cent of the 
prospective radio purchasers are governed 
to some extent by the amount of money 



12 



RADIO AGE for April, 1924 



The Magazine of the Hour 




FIGURE 3 

A more complicated and very efficient 
receiver is the Reinartz, illustrated in the 
above cut. A is the antenna, CI a 43- 
plate condenser, C2 a 23-plate (both 
should be vernier), and C3 is a fixed. 
.00025 MF grid condenser. AT are the 
antenna taps, GT the grid taps and PT 
the plate taps on the spiderweb induc- 
tance. R is a vernier rheostat, P the 
phones, and the batteries, PB for plate 
batteries, 22 s /2 volts, and FB the A bat- 
tery for the filament of the tube of suf- 
ficient pressure for the tube used. G is 
the ground connection. 



involved, while the other SO per cent care 
nothing about the cost, but are only inter- 
ested in getting the best apparatus that 
money can buy. 

Aerial Is Important 

There are many beginners who live in 
apartment in which the set is to be used 
to put an aerial on the roof and must, of 
course, have recourse to some kind of 
inside aerial, such as a loop or a wire 
stretched around the room, or in an attic. 
This also requires consideration. 

Contrary to the general idea that any 
kind of an aerial will suffice for an or- 
dinary crystal set, these sets should have 
the best possible antenna system, so that 
the already low efficiency of such a re- 
ceiver will not be hampered with a poor 
antenna system. It is much easier for a 
high powered tube set to function with a 
poor aerial than is the case with the 
weaker crystal set. The location of the 
apartment in which the set is to be used 
will also have to be considered. 

If one lives in an apartment on the first 
floor and must resort to an inside aerial, 
he cannot expect to get the results which 
he could get if he lived in a third floor 
apartment, as the height of the aerial 
makes an. enormous difference in the re- 
ception obtained. First, let us consider 
the beginner who is limited to a cheap 
set and wants to learn something about 
local broadcast reception. If it is a case 
where children are expected to handle it, 
it would be foolish to invest in a tube set 
until such a time that they learn some- 
thing about the general operation of such 
instruments. 

The crystal set, while not so powerful 
as a tube set,, will give one an idea of 
tuning and the delicate adjustments which 
must be obtained and at the same time 
will bring in broadcast entertainment very 
nicely. 

Outside Aerial Best 
But right here the beginner should un- 
derstand that simply because he has a set 
which is inexpensive and can be roughly 
treated that any kind of an aerial and 
ground connection will do. He must bear 
in mind the fact that in order to get the 
most out of it. that he should have the 



best aerial which he can make, in order 
that the efficiency, which is naturally low 
anyway in sets of this kind, will not be 
further reduced. 

If one has access to an outside aerial 
he should take advantage of it by all 
means. If this is not possible, he must, 
of course, resort to some kind of an inside 
aerial. Of course, the higher this is placed 
the better will be the reception, and one 
of the best aerials for this work is made 
by running an insulated wire around the 
room behind a picture molding. It should 
encircle the entire room once only, one 
end being left open and the other brought 
down to the set and connected to the 
aerial post and a wire connected to the 
ground binding post of the instrument 
should be run along the baseboard to some 
convenient water or steam pipe, where, 
after being careful to clean both the wire 
and the pipe until it is bright, it should 
be twisted around several times and fas- 
tened securely. This connection can also 
be made with a ground clamp which may 



be obtained at any radio store. 
Crystal Efficiency 

Now as to the type of crystal set to be 
used; one should select something that is 
good and substantial and has the best 
kind of tuning apparatus. If he builds 
the set himself, the arrangement shown in 
circuit No. 1 will be ideal for the pur- 
pose. With this arrangement, on account 
of its excellent tuning qualities, he may, 
if he is fortunate enough to have a fairly 
good aerial, be able to get not only the 
local broadcasting stations, but some of 
the distant ones as well. It is generally 
understood that a crystal set will only 
receive from distances of from twenty- 
five to forty miles, and this is true in 
regard to most of them, because of the 
poor tuning arrangements which they 
usually have, but the circuit shown has 
been designed to give the closest possible 
tuning and has proven worthy of the name 
of long distance crystal set. 

After one has become somewhat famil- 
(Continued. on page 36.) 




FIGURE 4 

An exceptionally close tuning receiver, a type highly desirable in sections where a 
powerful local station operates nearby. The tuning of this set is an art, and requires 
much patience, due to the fact that it is so sharp. The circuit is known as the 
Armstrong, also the Three-circuit regenerative, and. sometimes is called the Two 
Variometer, Variocoupler circuit. The letters bear the following values: A antenna, 
G ground, VI grid variometer, GL grid leak, 1-5 meg., Cl grid condenser, .00025 MF, 
fixed. V2 Plate variometer, FB filament battery, B plate battery and P the phones. 



RADIO AGE for April, 1924 



The Magazine of the Hour 



13 



The Wizard Ten Dollar Receiver 



Bv JOHN B. RATHBUN 



ABOUT two months ago, the writer 
was called upon to design a simple 
low priced set. A set which would 
have all the range of the Ultra-Audion 
and yet one which would have greater 
selectivity and which would be less noisy 
in operation. The controls were to be 
limited to two, the tuning control and 
the filament control of the tube, and the 
retail price of the unassembled parts was 
to be ten dollars or less. The result was 
a modified "jammer" or "Man-Day" cir- 
cuit with new trimmings, and this was 
given the trade name "Wizard." 

The original Man-Day circuit employed 
a standard variocoupler which intro- 
duced an extra control dial for moving 
the rotor and two tap switches for varying 
the inductance of the primary in addition 
to the tuning condenser. By employing 
a special fixed coupler with two stationary 
windings, somewhat similar to the neu- 
trodyne type transformer, the tuning con- 
trol was reduced to one unit — the variable 
condenser. This at once simplified the 
control and greatly reduced the expense 
of building the receiver, all without loss 
of selectivity or volume. The primary 
coil of the coupler is of the aperiodic 
type, while the secondary coil is alone 
tuned by the variable condenser. A po- 
tentiometer was added later as a means of 
more accurately controlling regeneration 
on faint signals and has proved its worth 
repeatedly. 

What Drawings Show 
In Figure 1 we have the circuit dia- 



gram of the modified Wizard circuit to- 
gether with a Bill of Materials which 
gives the names and sizes of the various 
units. Each of the binding posts is lo- 
cated in approximately the position that 
they occupy on the panel, and all of the 
wires are numbered to correspond with 
the numbered wires on the isometric 
drawing, Figure 3, of the assembled set. 
The binding posts are indicated by the 
small circles enclosing a solid black dot, 
and their arrangement is such that one 
or more stages of audio amplification can 
be added easily. 

Starting at the left of the diagram we 
see the fixed coupler having the primary 
coil (Ll) and the secondary coil (L2). 
The primary coil consists of 28 turns of 
No. 26 D. S. C. wire and the secondary 
contains 66 turns of the same wire. Both 
coils are wound on the same tube and are 
separated from each other by Y% inch as 
shown in Figure 2. The ends of the pri- 
mary coil go to the aerial and ground 
posts, while the ends of the secondary con- 
nect respectively with the grid condenser 
and moving arm of the potentiometer 
(PO). Full details of the coil are shown 
by Figure 2. 

Across the secondary coil (L2) is con- 
nected the vernier variable condenser (C) 
by which the circuit is tuned to the re- 
quired wave length. The tuning is very 
sharp and critical and a vernier condenser 
is therefore necessary for the best results. 
The whole arrangement is exceedingly 
selective for so simple a set, and like 
the neutrodvne, the condenser dial can be 



'■.Logged" or marked accurately for each 
wave length. To avoid trouble from body 
capacity it will be necessary to connect 
the stator or stationary plates of the con 
denser (C) to the grid line (4), while th. 
rotor connection goes to the potentiom- 
eter arm wire (5). For the sake of com- 
pactness, the coil (L1-L2) is attached to 
the condenser terminals by means of small 
sheet brass brackets in a manner familiar 
to those who have seen certain types of 
the neutrodyne. 

Best Condenser 

While a 17 plate condenser can be 
used at (C), Figure 1, in many cases, yet 
it is safest to use a 23 plate (0.0005) con- 
denser for this purpose in order that the 
full band of broadcasting wave lengths 
can be covered. With a larger condenser 
than this, the tuning is altogether too 
critical for comfort, even when equipped 
with a vernier. 

Experiments have shown that a value 
of 0.00025 mf is best for the grid con- 
denser (GC), and that the grid leak (GL) 
should be a variable leak, preferably of 
the lead pencil mark type. The lead 
pencil mark grid leak is adjusted by 
varying the thickness of a lead pencil 
mark drawn between two screws on the 
leak, and is the most effective and cheap- 
est of all leaks for this purpose. The tube 
is quite sensitive to grid leak values and 
a fixed leak does not give the best-results. 
Tubes vary among the same makes, and a 
different leak value must be determined 
by experiment for each individual tube. 




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RADIO AGE for April, 1924 




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A potentiometer (PO) acts like a ver- 
nier on the control of the regeneration and 
is necessary to clear up weak signals and 
to get the maximum signal strength. As 
originally designed, the potentiometer 
was omitted on the score of expense, but 
it is certain that it justifies the additional 
cost, particularly for those seeking dis- 
tance on their sets. An ordinary 200 ohm 
potentiometer is sufficient for this pur- 
pose, although a 400 ohm instrument 
gives still finer tuning. 

Rheostat 

At (R) is a vernier filament rheostat, 
the resistance of which depends upon the 
tube For a UV-200 or C-300 detector 
tube, a 6 to 7 ohm rheostat is best. The 
the UV-201A or C-301A tube a 25 ohm 
rheostat is best, although a 15 ohm rheo- 
stat can be made to answer. The UV-199 
or C-299 tube calls for a 30 to 40 ohm 
rheostat. In circuits of this sort, the 
control of regeneration is controlled prin- 
cipally by the rheostat and potentiometer, 
hence a vernier type gives the closest 
tuning and the greater distance. With 
a plain rheostat the change in resistance 
between two turns of wire is too great 
for proper control. 

Of course a six volt power tube is the 
best, the writer having the best results 
with the C-301A or UV-201A Next 
comes the UV-199 or C-299 tube, which 
operates on three dry cells. Good results 
can be had with the WD-11 or WD-12, 
but as these tubes tend to broaden the 
tuning the set is not so selective when 
they are used. The same rheostat is used 
with the WD-11 as with the C-300 or 
UV-200 detector tubes. Soft detector 
tubes such as the UV-200 or C-300 work 
quite well at plate voltages ranging be- 
tween 16 and 22.5, but are not suited for 
the higher "B" battery voltages, which 
are instrumental in long distance work 
and loud local signals. 



With a hard tube such as the C-301A 
or UV-199, we can carry a "B" battery 
voltage of from 45 to 90 volts with great 
success. With the average tube, maxi- 
mum signal strength is attained at about 
67 volts or with three 22.5 volt "B" bat- 
tery blocks connected in series. This gives 
tremendous volume on local stations, but 
cannot be used on the soft detector tubes. 
High plate voltages increase the sharp- 
ness of the tuning, but at the same time 
increase -the noise and the tendency for 
the tube to "tip" over when the rheostat 
is adjusted. In radio there is never any 
gain without some corresponding loss. 

Follow Instructions 

On carefully following the circuit dia- 
gram, Figure 1, it will be seen that the 
coupler coil (Ll) acts not only as a pri- 
mary coil in the aerial circuit, but that 
it acts as a tickler coil as well since it is 
in series with the "B" battery and plate 
(P) of the tube. This means that the 
spacing between the primary and secon- 
dary coils (Ll) and (L2) is of importance 
in order that we gain the maximum re- 
generation without excessive sensitiveness 
on the part of the rheostat adjustment. 
Again, the spacing of the coils controls the 
degree of "loose coupling" between the 
primary and secondary and therefore the 
degree of selectivity. If fewer turns are 
used in (Ll) than shown, we will have 
increased our selectivity, but will have to 
burn the tube brighter to make up for the 
loss in feed-back. The proportions are 
a compromise arrived at by experiment, 
and should not be changed. 

The tube ordinarily supplied for this 
circuit has an internal diameter of 2.5 
inches or an external diameter of 2 11 ,'ifl 
inches. This may be either a bakelite tube 
or plain cardboard, but a bakelite tube is 
best as it does not shrink and loosen the 
windings. When a 3-inch tube is used, 
take off two turns on both the coils (Ll) 



The Magazine of the Hour 

and (L2) because of the increased length 
of wire and the greater inductance and 
wave length. If you cannot reach the 
lower wave lengths at any adjustment of 
the condenser (C), then remove a few 
turns from the coil (L2) at the outer end. 
This will reduce the wave length. Much 
depends upon the length of your aerial 
as to the wave length range, a long aerial 
requiring fewer turns than a short aerial. 
A very long aerial, exceeding 100 feet in 
length, has a decided tendency toward 
reducing the selectivity and therefore 
should be avoided. The ideal length for 
locations where there is much trouble 
from interference is about 60 feet. 

Direction of Windings 

About the only trouble that has been 
experienced by amateurs in building this 
set is that of "Bucking" or reversed coils. 
Both coils (Ll) and (L2) must be wound 
in the same direction around the tube, and 
must then be connected up so that the 
primary current, feed-back current and 
secondary currents all flow in the same 
direction. If the set does not prove 
sharply selective when hooked up, or if 
the signals are weak, then try the effect 
of reversing the primary coil connections 
(a) and (b). This should immediately 
improve the performance if the coils were 
opposed or bucking each other. Best con- 
nect up (a) and (b) temporarily at first 
until we determine the proper connection 
to make by experiment. The direction of 
winding, whether right hand or left hand, 
makes no difference as long as both coils 
are wound in the same direction. 

A panel 7 inches by 9 inches by :! in inch 
will be amply large for this set, and it 
has been mounted on a panel as small as 
6 inches by 7 inches. Both of these 
panels are standard sizes and are easily 
obtained at a radio store. Cabinet and 
baseboards are easily found for these sizes 
of panels. 

To reduce the cost of building to a mini- 
mum, we can omit the potentiometer (PO) 
and then connect the end of the wire (5) 
to the point where the ends of wires (9) 
and (13) are connected. Thus, without 
the potentiometer, the wires (5), (9) and 
(13) are all connected together at a com- 
mon point, leaving wires (12) and (11) 
as before. 



Radio's Expansion 

Educational institutions and newspapers 
have recognized the value of broadcast- 
ing, it is indicated by the February Radio 
Service Bulletin, issued by the Bureau of 
Navigation of the Department of Com- 
merce. And there is an increasing num- 
ber of churches which have found the 
radio an effective aid in their work. 

The latest list of stations broadcasting 
weather reports, music concerts and lec- 
tures shows ninety-five broadcasting sta- 
tions connected with universities, colleges 
and other schools. The same directory 
lists forty-six newspapers or publishing 
houses, which have their broadcasting 
stations; while twenty churches are shown 
in the lists. This does not. however, in- 
clude a number of churches whose serv- 
ices are broadcasted through some other 
station, it was pointed out. 



RADIO AGE for April, 1924 



The Magazine of the Hour 15 



Note! 

/IS SEVERAL 0F THE W//Z&S /?/VD C0/VWGCT/0A/S 
/?&£ H/0OE/V &EH/MD 7ME CO/L/9/VL? COMDEA/&E& 

/T/ss/frasr to check- up the wir/ng below 

&YME/)HSa/? TH£ W/R/MG D/AGR/9M J-HOW/V 
ELSEWH£~/?E. SOCDE& ALL JOtfVTS. 




FIG. 3 

W/z/ikd C/rguit(Re/ir) 

W//FES /4/emMt/Af/3Efr£:D TO CO* > /?£r<S-/?OA/& 
W/TH THE? W/frE Nl/MBe/e/MBON T/Y£~ C//?- 
COIT D/sVtS/e^M &HOW/V EiLS'ElA/HE.'rE:. FOL- 
LOW COA/A'£CTf<2/VS- &/V £>/s?<5-/&?/*7s 



Guarding Against Body Capacity Effect 



WHEN the grid line or other partb 
connected with the grid post of 
the vacuum tube socket are 
raised to a relatively high potential by 
regeneration or radio frequency amplifi- 
cation, when a very noticeable electro 
statjc field is set up about these part; 
which seriously interferes with the opera- 
tion of the receiving set. Moving the 
hand or any other conductor in the elec- 
trostatic zone causes momentary varia- 
tions in the capacity of the circuit which 
may completely detune the receiver or 
cause it to shriek badly. This effect is 
not confined to the immediate vicinity 
of the grid circuit, but may even extend 
for several feet around the set under 
extreme conditions so that a person walk- 



By ROSCOE BUNDY 

ing past may cause the set to become 
completely detuned. This effect is called 
"body capacity" and is one of the most 
troublesome diseases to which a set may 
fall heir. 

In the milder forms, body capacity is 
confined to the tuning controls, the tuning 
being affected only when the hand is re- 
moved from the variable condenser or 
variometer knobs. A station can be tuned 
in very accurately while the hand is on 
the dial, but as soon as the hand is re- 
mo\ed, the signals disappear or the set 
will begin to howl. As a rule, this is most 
noticeable on faint signals from distant 
stations, and is not always in evidence 
on strong local signals where regeneration 
or amplification is not being pushed to 



the limit. In the more severe cases, tht; 
body capacity effect may extend to other 
parts of the circuit, causing still more 
trouble and trouble that is far more 
difficult to cure. Certain single circui 
receivers, such as the Ultra-audio o< 
Flewelling, frequently develop "phone 
cord capacity" in which a strong electro 
static field exists in the head set and 
phone cords. Every time that we movi 
our head or touch the earpieces or cord, 
the set is either detuned or else it start: i 
to howl. Any circuit in which the plati 
is conductively connected with the grid iv 
likely to have this trouble to a greatei 
or less extent. 

To reduce body capacity in the con- 
trol system, we must first keep all parts 



16 



RADIO AGE for April, 1924 



The Magazine of the Hour 



<cr^- 



6kO 



SOCKET 




&<$./ 



connected with the grid as far back of 
the panel as possible. This is rule No. 1. 
This refers not only to the wiring of the 
grid lines but to the grid condenser, leak 
and variable tuning condenser parts as 
well. Where a grid variometer is used it 
is of particular importance to keep this 
instrument as far in the background as 
possible, and to arrange matters so that 
the charged shaft does not bring the 
charge up as far as the panel. That part 
of the shaft which carries the dial and 
which projects in front of the panel will 
bring the electrostatic field forward just 
as surely as the windings or body of the 
instrument itself. Further, the charged 
shaft comes right into the dial where it 
is directly subjected to the condenser 
effect of the fingers and where it is in 
exactly the right position to cause trou- 
ble. It should be remembered that any 
amount of dial insulation surrounding the 
shaft will have no effect on the electro- 
static field. We cannot insulate against 
an electrostatic charge in the same way 
that we insulate a current carrying part, 
but we can prevent the charge from com- 
ing forward by using a shaft of insulating 
material such as a rod of bakelite or hard 
rubber. 

It is a far simpler matter to reduce the 
body capacity effect with the variable 
tuning condenser in the secondary circuit 
than with a variometer for the reason 
that the two halves of the condenser are 
well insulated from one another. With 
a condenser, the stator should be con- 
nected to the grid line, while the rotor 
and shaft are connected to the grounded 
part of the circuit. This follows from 
the fact that the stator or stationary 
plates are located well back of the panel, 
while the rotor is mounted on the shaft 
and hence would bring the grid charge 



forward were the rotor connected to the 
grid line. 

Figure 1 shows a variable condenser 
having the rotor or movable plates (m) 
mounted directly on the shaft with the 
shaft stub (X) projecting beyond the 
front of the panel. If the rotor and shaft 
are connected to the grid post (G) 
through the grid condenser (GC) and the 
grid leak (GL), then it is certain that 
the front end of the shaft (X) will be 
at grid potential and that there will be 



it is common practice to ground the 
( — A) line of a receiver so that the 
charge on the controls is reduced. In 
single circuit sets the I — A) is nearly 
always grounded, but in two and three 
circuit receivers it may be necessary or 
desirable to run a separate ground wire 
to the ( — A) line at some point. Ground- 
ing the ( — A) does not completely elimi- 
nate body capacity in every case, but is 
at least of assistance. In making such 
ground connections, one should be certain 
that the ground does not cause a short 
circuit. 

Shielding the various parts of the cir- 
cuit is a last resort as it usually reduces 
the signal strength to a certain extent, but 
when properly applied it is the most 
effective means. In Figure 1 a thin sheet 
of metal (P) called a "shield" is placed 
between the condenser and the back of 
the panel, and this shield is then grounded 
to the ground post of the set. This 
grounds the greater part of the electro- 
static field that would reach the hand 
and hence reduces capacity effect. Sheet 
brass, tin foil or sheet aluminum are 
used for this purpose, but it should be 
noted that the shield is not in the least 
effective unless connected to ground. The 




trouble with body capacity if a sufficient 
potential is established on the grid by 
regeneration. If the grid line is con- 
nected to the stationary plates or stator 
(S), then all parts at grid potential will 
be located well back of the panel and the 
tendency toward body capacity on the 
controls will be reduced by this amount. 
Again, connecting the stator to the grid 
allows us to connect the rotor to the 
ground or to ( — A), which still further 
protects against trouble. 

It should be noted at this point that 



<Bi_ 




<5.G. 



GL 




- A + 



metal ungrounded simply affords an ex- 
cellent means of carrying the field still 
further to the front, just as with any 
other conductor. Placing a disc of metal 
on the inside of the dial and then ground- 
ing the disc through a brush is still an- 
other method of shielding employed by 
makers of certain condensers. 

As a rule, the shield should be installed 
as far away from the charged surfaces of 
the condenser plates or variometer wind- 
ings as possible, so as to reduce losses 
which take place to the grounded plate. 
Where possible the condenser should be 
moved back from the panel as far as the 
length of the shaft will permit, and then 
the shield will be at least l /> inch from 
the plates. Care must also be taken to 
cut out the p'ate for some distance around 
the shaft hole and condenser screws so 
that the condenser will not be short cir- 
suited or grounded. 

• Figure 2 is a diagram of a single circuit 
tuner where the ( — A) is grounded na- 
turally by the arrangement of the circuit. 
The stator plates (S) of the condenser 
(C) are connected to the grid while the 
rotor plates (m) go to the ( — A) and 
ground as should be the case. Dotted 
lines represent the shielding and shield 
(Continued on page 51.) 



RADIO AGE -for April, 1924 The Magazine of the Hour 17 

Radio Frequency Amplification 

With Interstage Transformers 
By P. E. Edelman 



RADIO freqency amplification ahead 
of detection is used to boost the 
radio frequency current to suffi- 
cient value so that good operation results 
on distant signals. The general methods 
are: 

1. Combined with regeneration. 

2. Transformer interstage coupling, 
tuned or untuned. 

3. Impendance or resistance coup- 
ling 

4. Frequency conversion plus meth- 
od (2) or (3), as in superhetero- 
dyne, etc. 

5. Modifications of method (2) 
with means to stabilize. 

Radio amplification before detection 
avoids distortion such as is liable to occur 
when two or three stages of audio ampli- 




fication are used, and permits very weak 
incoming energy to be built up so that the 
detector will operate as well as on strong 
radio signals. Unless the rectifying abil- 
ity of the detector is also increased there 
is little advantage in increasing the num- 
ber of stages of radio frequency amplifica- 
tion beyond the point which gives suffi- 
cient radio frequency output to fully oper- 
ate the detector. That is why with usual 
radio amplifiers, local stations are only 
heard as loud as the detector output with 
full radio input permits. Sometimes radio 
amplification is said to increase range but 
not volume, but if means are provided to 
use all the radio output of the amplifier 
it is possible to get loud volume without 
further audio amplification or with only 
one additional stage of it. 

To get full benefit of radio amplification 
on strong incoming radio energy it is nec- 
essary to increase the ability of the de- 
tector to handle the increased energy and 
rectify all of it. The usual detector tube 
will not do this, as its output is limited. 
It is customary to employ enough radio 
amplification to operate the detector on 
distant signals and reduce the radio input 
or turn down the amplifier tube filaments 
when listening to local stations. 

Transformer Interstage Coupling 
The most popular and generally used 
interstage coupling for radio amplifiers is 
afforded by transformers and will now be 
discussed. Special forms of coils are 



often used but are not essential. Ordi- 
nary coils in the form of variocouplers, 
inductance coils, spiderwebs, honeycombs, 
etc., may be used. The essential features 
are to minimize capacity, effects, and 
secure good inductive transfer of energy 
from one out-put to the next input cir- 
cuit. 

Tuned Transformer Circuits 

Tuned transformer circuits afford very 
good frequency selection for tuning pur- 
poses. This is noticeable when only one 
stage is used and very marked when two 
tuned stages are employed. Some sets 
use three or more tuned stages but even 
when two stages are thus used, the con- 
trol is complicated for a beginner's use 
unless some mechanical means is used to 
adjust two or more circuits simultane- 
ously. A good design may use two or 
more stages of radio amplification with 
only the input circuit tuned or perhaps 
with one stage only tuned. The latter 
arrangement can be made sufficiently se- 
lective to work through local stations. 

Stabilizing Circuits 

Transformer coupled radio amplifying 
circuits require some stabilizing means to 
avoid oscillating effects. This is particu- 
larly true of tuned interstage coupling. 
Some methods used are: 

1. Resistance (50 to 400 ohms) 
inserted in grid or plate circuit or 



YOUNGEST STATION MAN 
The interior of Station WABQ, broadcasting station of the HAVERFORD COLLEGE RADIO CLUB, Haverford, Pa. 
and (left inset) William S. Halstead, station manager and designer. Although only 20 years old, Mr. Halstead designed 
and personally supervised the building of this station. Mr Halstead started in 1912, experimenting with spark coils when 
8 years of age, he is member Institute Radio Engineers. He is, no doubt, the youngest Radio Broadcasting manager in the 
world. Photo shows receiving table, speech amplifiers, and short wave transmitter (amateur call 3 BVN.) Left to right, 
main receiver and 2 stage amplifier used as "stand by" set for S.O.S. calls. The short wave receiver has brought in seven 
foreign amateurs, French 8AB on loud speaker, as well as eight Pacific Coast stations. Power amplifier, Horn, A. R. R. L. 
message file, change-over switch, telephone and wave-trap. 



18 



RADIO AGE for April, 1924 



The Magazine of the Hour 



incorporated in windings of trans- 
formers. 

2. Grid current established by ap- 
plying small positive operating poten- 
tial to grid of one or more tubes 
used. Potentiometers are much used 
for this purpose. A resistance of 
50,000 ohms upwards might also be 
shunted across the grid and filament. 

3. Absorbing circuits in grid or 
plate circuit. These work like a 
wavetrap or provide a parallel current 
path. 

4. Reflex audio input, setting up 
variation potential in grid circuit. 

5. Counter electromotive force 
applied to grid circuit. Reversed re- 
generation coupling does this. 

6 Shunt resistance by establish- 
ing a separate energy using circuit 
between plate and grid circuits. 

7. Critical adjustment of coupling 
values used. 

8. Use of loose coupling with un- 
tuned primary and tuned seconda-y 
usually 7 to 10 turns primary and 50 
to 60 turns in the secondary coil. 

9. Divided circuits. 

10. Neutralizing by sending oppos 



ing potential through small condenser 

to either grid or plate from either 

plate or grid circuit. 

Some of these methods, as is obvious, 
are automatic and others require adjust- 
ment to fit different frequency values. 

Air Core Transformers 
Tuned transformers will usually be air 
core type and have variometer or shunted 
condenser form of tuning. It is usual to 
keep them of small size to avoid estab'ish- 
ment of extensive radio frequency fields. 
Sometimes this point is not regarded and 
interferences result from intercoupling be- 
tween transformers or a transformer and 
a loop coil used with the set. It is de- 
sirable in reflex circuits to keep the capac- 
ity effect between the windings very small, 
so as not to pass cons ; derab!e audio cur- 
rents by condenser action. This is usually 
accomplished by separating the two wind- 
ings. Air core transformers are sometimes 
used without adjustable tuning means and 
can be made to cover limited frequency 
bands efficiently. They are wound to have 
minimum self capacity and are made of 
.-.mal! dimensions. 




PORTO RICO IS BITTEN 
Radio is fast becoming popular in Porto Rico. These native society girls ara 
seen listening-in to concerts from the States. Left to right — Miss Lydia Rexach, 
Miss Adela Gomez, Miss Emilia Rexach 



Iron Core Transformers 
Iron core transformers based on the 
suggestion of Mr. Latour use very thin 
laminated soft steel for a core. The iron 
is of tissue thinness. Its effect is to both 
concentrate the field and prevent external 
leakage, thus increasing the impedance for 
a range of frequencies, and also to supply 
a capacity effect for the coils. Some types 
of untuned transformers use powdered 
iron or powdered iron held in wax as a 
core. The effect is to broaden out the 
range of frequency response, but usually 
such transformers are better at one or two 
narrow bands of frequency than others. 
Some transformers are wound with fine or 
resistance wire to further broaden out the 
frequency range but this may reduce th? 
energy transfer and mitigate against high 
amplification. The best results with such 
transformers are obtained when correct 
balance of the windings is obtained to fit 
in with the characteristics of the ampli- 
fying tube used. 

The use of iron core transformers or 
other types of untuned transformers is 
seldom carried on beyond two or three 
stages. Combinations of one stage tuned 
transformer coupling with one or two 
untuned stages afford a simple and selec- 
tive design. 

Continuously Variable Couplings 
The primary and secondary windings, 
one or both, can be made adjustable to 
fit different frequencies while maintaining 
good coupling for efficient transfer of 
energy. This is accomplished by double 
coupled variometers or sometimes by use 
of tapped coils. 

Transformers also find. use in complex 
circuits on the super-heterodyne principle, 
where amplification is cascaded at a par- 
ticular frequency such as 100.000 cycles to 
which incoming frequencies are trans- 
ferred by heterodyne methods. 

Regenerating Effect 
As used in some circuits, fixed or tun- 
able transformers have regenerating cir- 
cuit effects. Sometimes the non-regener- 
ative amplification is mentioned as distin- 
guishable from the combined amplication 
possible at radio frequencies. 

Relative Value of Stages 
One good stage of tuned radio amplifica- 
tion will sometimes equal two untuned 
stages. When two stages give good de- 
tector response on distant signals, a fur- 
ther stage is often no advantage. Just 
now, transformer coupled stages are per- 
forming fairly well but there is room for 
improvement. This may be in the trans- 
formers, the circuits, or the tubes used, 
one or all. 

Practical Use of Transformers 
The practical use of transformers re- 
quires care in wiring with minimum 
lengths of carefully insulated or spaced 
wiring. Very small condenser effects in 
adjacent wires can transfer radio energy 
away from the transformer. That is an- 
other reason why small dimensioned trans- 
formers are desirable, as the length of 
connecting wires is smaller. 

Impedance Coupling 

Impedance coupling as used in many 
sets is a form of transformer coupling in 
which only one winding is required. Re- 



RADIO AGE /or April, 1924 



The Magazine of the Hour 19 




BROADCASTING PICTURES 

Stewart W. Jenks, Raido Engineer, is seen at work in the C. Francis Jenkins studios, broadcasting radio pictures. This 
broadcasting station has a range of thirty-five miles and will transmit motion pictures, still pictures, and music. This is the 
latest development by Mr. Jenkins, after ten years of research. 

Reflexing the R. F* Variometer Addition 

Bv BRAINARD FOOTE 



STILL further advantage may be 
taken of the radio frequency addi- 
tion to the standard variometer re- 
generative set by means of employing 
reflex action on the radio frequency tube. 
This plan has a good many desirable fea- 
tures, although there is a drawback as 
well. The item of expense is not so seri- 
ous, inasmuch as the reflex change-over 
merely means the insertion of an audio 
frequency transformer and another by- 
pass condenser. 

In point of operation, several improve- 
ments are derived. In the first place, 
the Volume received will be many times 
what it was with the straight radio fre- 
quency tube, sufficient in the case of most 
of the local stations to put on a loud 
speaker. The volume, it is true, is not 
quite as great as it would be were the fir^i 
tube used straight, and an extra tube as 
plain audio frequency added after the 
detector. However, it is nearly so, and 
a worth-while saving in expense is the 
Tsult. 



Operating Characteristics 
The reflex is not quite as stable a cir- 
cuit as the straight radio addition, and 
when pushed past the oscillating point, is 
prone to howl quite unmercifully. The 
howl is caused by an audio frequency 
feed-back from the plate circuit of the 
R, F. tube to its grid circuit because of 
the fact that the tube is used not only as 
the R. F. amplifier but as the A. F. am- 
plifier as well. The tendency to squeal 
is lessened by the use of a low ratio 
transformer — 3 to 1 or 4 to 1. 

However, there is really no need to 
force the set into oscillation, for very 
little is gained in the way of sensitive- 
ness by so do'ng. and all the DX stations 
that are heard without reflexing the circuit 
come in a eond deal louder with the 
reflex added. 

Little room is needed inside the set. 
and the audio transformer can be mounted 
somewhere in the vicinity of the left 
hand variometer — right behind it, per- 
haps Besides the transformer, a .002 



fixed condenser is needed. Figure 4 gives 
the complete wiring diagram, and points 
out the differences between the plain cir- 
cuit of Figure 3. The phones are taken 
out of the plate circuit of the detector 
tube and are replaced by the primary 
connections of the audio transformer. 
The .001 by-pass condenser is just as 
necessary as ever. 

Then the lead running from the switch 
lever of the coupler to the "B" battery 
positive is disconnected, and the phones 
inserted between these two points. In- 
asmuch as the phone windings offer a 
high impedance to the radio frequency 
currents flowing through the primary of 
the coupler, it is necessary to shunt them 
by a 002 fixed condenser, connected be- 
tween the above-mentioned switch lever 
and the negative side of the filament. 

How It Works 
Then the "grid return" lead from the 
left land variometer to the negative of 
the "A" battery is removed, and the sec- 
ondary connections of the transfer sub- 



20 



RADIO AGE for April, 1924 



The Magazine of the Hour 




stituted instead. Many reflex circuits 
show a large fixed condenser across the 
"G" and "F" posts of the transformer, 
but the experience of the writer is that 
this is poor practice in a single reflexed 
tube. It acts as a shunt condenser and 
lowers the voltage of the energy released 
from the secondary winding, thereby re- 
ducing the volume very noticeably 

It is usually stated that this condenser 
is required in order to cause oscillation, 
but with a vario-coupler as the R. F. 
transformer, there are so many extra 
turns available for feeding back the 
energy causing oscillating that it is easy 
to set the circuit very close to the oscil- 
lating point or in fact to cause it to 
oscillate. This is seldom done because 
of the howling spoken about already. 

The energy traversing the antenna cou- 
pling coil (seven turns of bell wire — coil 
L of Figs. 3 and 4 — coupled to the first 
variometer) is transferred to the variom- 
eter, whose effective wave range has been 
raised by a small shunt capacity "C" of 
the order of .0002 mfds. The voltage is 
applied to the grid, where it sets up a 
much stronger fluctuation of the plate 
current supplied by the 90 volt "B" bat- 
tery. This in turn, passes through a por- 
tion of the vario-.coupler's primary wind- 
ing, from which energy is transferred to 
the rotor. The grid circuit of the de- 
tector is tuned by another variometer 

The Tuning Method 
The actual tuning is done by the two 
variometers, and the scale readings of 
one of them should be noted down for 
reference. There is only one position 
of the other variometer which corre- 
sponds to any particular setting of the 
first one, so that the adjustment of the 
set is easy enough. The switches are set 
to include enough turns of the coupler's 
primary winding to bring the set to the 
verge of oscillation without really allow- 
ing oscillations to begin. The rotor is 
left at maximum coupling all of the time 
The best method for tuning the set, 
once a list of the dial settings for the 
stations most ordinarily heard has been 
written down, is to work from a simple 
graph. This is made on a sheet of cross- 
section paper, drawing a horizontal line 
near the bottom and dividing that into 
equally spaced divisions for the dial read- 
ings, and then drawing a vertical line at 
the left border. This latter is used for 
the wave length indications, from about 
250 to 550 meters. The points of inter- 
section for all the stations heard are 



marked down on the proper places, and a 
SMOOTH curve drawn passing through 
the points as evenly as possible. 

Then it becomes easy to look up the 
dial setting for any other wave length 
and to tune for a desired station whose 
wave length is listed in the evening's pro- 
grams, but which has not previously been 
heard. The graph also aids in the identi- 
fication of an unknown station because it 
will tell the wave length of a station tuned 
in at some particular dial degree. Such a 
method of tuning cannot, of course, be 
followed with the ordinary double or 
triple circuit set because of the fact that 
the coupling variations upset the other 
dial readings, but with tuned radio fre- 
quency, the plan is highly satisfactory. 



RCA Finances 

Maj. Gen. G. Harbord, president of 
The Radio Corporation of America, has 
made the following statement: 

"The Radio Corporation will, this year, 
pay the 7 per cent dividend on its pre- 
ferred stock, which is cumulative from 
the first of January, 1924. 

"It is anticipated that at the meeting 
"of the stockholders to be held in May, 
the charter of the corporation will be 
amended so as to reduce the number of 
shares of authorized preferred stock from 
5,000,000 to 500,000 and the authorized 
no par value common stock from 7,500.000 
to 1,500,000 shares. The plan is to re- 
tain the capitalization of the corporation 
as at present authorized, but to create a 
par value of $50 for the preferred stock, 
to be known as 'A' preferred stock, for 
which the present preferred stock will be 
exchangeable at ten shares of the present 
for one share of the new stock and to 
exchange the present common stock at the 
ratio of five shares of the present stock 
for one share of the new or 'A' common 
stock. 

"The exchange in cases where the pres- 
ent stock is not held in multiples of ten 
and five shares will be facilitated by the 
issuance of fractional shares of the new 
stock. 

"The 'A' preferred stock will be en- 
titled to receive 7 per cent dividends, 
payable quarterly, cumulative from Jan- 
uary 1, 1924, the payment for the first 
two quarters of 1924 to be made in July 
Shares of the present preferred stock not 
converted into the new, and fractional 
shares resulting from uneven multiples 
will receive the 7 per cent dividend, pay- 
able, as may be determined by the board 



of directors, but cumulative from Jan- 
uary 1, 1924. Stockholders who have not 
exchanged their preferred stock in time 
for a particular dividend date on the 'A' 
preferred stock, will be entitled to any 
accrued and declared dividends on said 
'A' preferred stock after they make such 
conversion. 

"The dividend rights of the preferred 
stock over the common stock, and the 
voting rights of each, will be preserved in 
this arrangement. 

"After this change is effected, applica- 
tion will be made to list the 'A' preferred 
and the 'A' common stock on the New 
York Stock Exchange." 



Spotting Interference 

Hartford, Conn. — As the interruptions 
to broadcast programs from defective 
lighting circuits are common in nearly 
every city, the difficulties recently over- 
come here by radio amateurs in coopera- 
tion with the city electric light company, 
are of more than local interest. Com- 
plaints from listeners became so pro- 
nounced that the Radio Club of Hartford 
named a special committee to run down 
the source of trouble by means of a loop 
receiver. 

This committee set out upon its task in 
a businesslike manner by preparing first 
a map of the section of the city from 
which it was believed most of the inter- 
ference came. On the map pins were 
placed with numbered flags glued to them. 
Perry O. Briggs, local amateur, who de- 
vised the system, then placed a small loop 
set in an automobile and directed its 
movements. 

These flags were shifted as the "buz- 
zing" sounds came and went until all of 
the bad spots had been plotted out. When 
the results were given to the Hartford 
Electric Light Company it went so far 
in one case as to replace the entire circuit 
in one street. The improvement since this 
was done has been very gratifying 



Slogans for WAAW 

The Omaha Grain Exchange put on a 
slogan contest at WAAW recently, the 
slogan consisting of words beginning with 
the call letters of the station. The con- 
test was not announced until 8 p. m. and 
a large stack of telegrams was on hand 
at 10 p. m., when the contest closed. 
First prize of $10 was won by Harvey C. 
Dendall, Lincoln, Neb., with the slogan: 
"Where Agriculture Accumulates Wealth " 
For the most amusing slogan a special 
prize of $10 was awarded to J. B. Fickel, 
of Hastings, la. His slogan was: "Was 
Adam's Apple Wormy?" 



Bradleystat Chosen 

The American Radio Research Corp., 
Medford Hillside, Mass., has adopted the 
Bradleystat and Bradleyleak as standard 
equipment in all their expensive console 
and table models. These two Allen-Brad- 
ley products were selected and adopted 
after extensive research by the Amrud 
engineers. 



RADIO AGE for April, 1924 



The Magazine of the Hour 21 




Icicle 

Hook" 





In the February, 1924, issue we pub- 
lished a couple of photographs of Mr. T. 
J. Kennedy showing his trans-Atlantic re- 
ceiver, and gave his address in the caption 
underlining the photograph. Permit us to 
direct your attention to the following let- 
ter, a reply to our publication of the 
photographs. 

RADIO AGE, 
Gentlemen : 

Since you published a photo of my 
honeycomb receiver, I have been 
swamped with letters from your read- 
ers, and I am unable to answer all 
the inquiries, which would require 
several stenographers to attend to the 
mail. 

I am enclosing herewith a complete 
account of the reception and set. If 



1923, made and operated my first 
honeycomb receiver. 

Since then I have stuck pretty 
closely to this one outfit, perfecting 
it, making little changes here and 
there, with the object of making a 
more efficient receiver. 

I use three honeycombs in the fol- 
lowing manner: For the antenna I 
find that an L35 is effective, with an 
L50 for the secondary and 175 for 
the tickler. These honeycomb coils 
are seldom if ever touched, but are 
placed at a certain distance from 
each other and left there. The sec- 
ondary is in the middle, with the pri- 
mary on the left and the tickler on 
the right. The primary is just a lit- 
tle further away from the secondary 
than is the tickler coil. I use a 23- 



CONTRIBUTORS 



T. J. Kennedy 



F. Robert Zeit 



Joseph W. Pfister 



DIAL TWISTERS 



Name 



Address 



Circuit 

C. R. Williams 433 Milton Ave., Janesville, Wis Zenith 

H. G. Ende 1S01 Sedgwick St. Chicago, ill Single Circuit 

Joseph J. Oswald 433 Emory Ave., Trenton, N. J ... .Not Stated 

Bennie S : vesind Decorah, Iowa Single Circuit 

H. F. Willis 1200 Fairfield Ave., Shreveport, La Single Circuit 

J. H. Kulp Z23 Clifford Ct., Madison, Wis ,. .Three Circuit 

John Tomlin 303 Madison Ave., Atlantic City, N. J Not Stated 

Bireley Ross 806 Brazos St., Graham, Texas Not Stated 

R. B. Hamilton 674 S. Capital St., Salem, Ore Cockaday 

Robert Signaigo 4170 Connecticut St., St. Louis, Mo Crystal 



plate vernier condenser of General 
Radio make in both ground and sec- 
ondary circuits. The ground con- 
denser is used very little in tuning 
after being once adjusted. The sec- 
ondary condenser and the filament 
rheostat for the detector are the 
major controls which I manipulate, 
once the preliminary adjustments 
have been made. The detector is a 
C301A and despite the general belief 
to the contrary, I find that it is highly 
efficient. 

I have placed a 3-inch dial on the 
shaft of the detector rheostat which 
is of the best quality, and operate 
upon the dial, a vernier of the fric- 
tion type, which gives me the closest 
possible control over the detector 
tube current. With this filament 
control and extremely accurate tun- 
ing with the secondary condenser, I 
am able to build up DX signals to 
the most astonishing volume. Occa- 
sionally a slight adjustment is neces- 
sary on the potentiometer, and less 
frequently a slight movement of one 
or two of the other controls. The 
potentiometer, by the way, is 400- 
ohm, graphite type, which I think is 
superior to the wire types, the latter 
causing noises in the headset. 

I am absolutely averse to jacks, 
feeling that they are responsible for 
nearly nine-tenths of the noises in 
circuits. I am even contemplating 
the removal of the jack in the last 
stage, as I feel confident that I can 
further improve the general efficiency 



you care to publish same for the sake 
of your readers, you sure are welcome 
to it. 

Yours for good radio, 

THOMAS J. KENNEDY. 
232 West 55th St., New York, N. Y. 
The length of Mr. Kennedy's account 
of the set and record breaking reception 
is too great for our use, but we take pleas- 
ure in presenting herewith some of the 
high lights and pointers which seem to be 
the leading factors in Mr. Kennedy's ac- 
complishment. 

Mr. Kennedy, in contending that Lon- 
don and Los Angeles can be tuned in on 
an old-fashioned honeycomb coil set, using 
a detector and two stages of audio fre- 
quency amplification, points out that 
among the chief reasons for his remark- 
able success are the following: 

After my first experiments with the 
customary crystal sets, which I soon 
found to be too limited, I made a 
three-circuit regenerative set, which 
consisted of two variometers and a 
variocoupler. I found that this too 
had limitations, and around February, 




A DISTANCE GETTER 
Thomas J. Kennedy, 470 West 159th Street, N. Y., regularly receives 2-LO, of 
London, Eng., and KHJ, Los Angeles, with this simple three-circuit honeycomb 
regenerative set. He tunes with the secondary condenser and the rheostat of the 
detector tube, without moving the honeycomb coils or the ground condenser. Note 
how he uses condensers and grid leaks across the transformer secondaries to clear 
up signals. (Kadel & Herbert.) 



22 RADIO AGE for April, 1924 




A DISTINGUISHED RADIO FAN 
HUDSON MAXIM, noted inventor, whose nephew Hiram Percy Maxim is 
President of the American Radio Relay League, listening in to the address of 
President Coolidge, from Hotel Belclaire. 



of the receiver by making this change. 
I entirely disclaim this high ratio first 
stage transformer propaganda, and 
think that two low ratio transformers 
are better. 

My main object in building and ex- 
perimenting with this receiver was to 
eliminate all the usual set noises, and 
I went to a lot of trouble and expense 
to accomplish this. I found that a 
.00025 MF fixed condenser across the 
secondaries of each of the trans- 
formers assisted materially in this 
respect. I further found that by 
placing grid leaks across these con- 
densers I was further able to elimi- 
nate noises, and in the course of my 
experiments found that a 2J/2 meg- 
ohm leak on the first transformer and 
a 3 megohm leak on the second 
seemed to work best. This is, how- 
ever, a matter of individual experi- 
ment, and is entirely up to the builder 
as to which is the most effective. 
Variable grid leaks are absolutely 
useless in any part of the circuit. 
The C battery should also bz care- 
fully adjusted 



Another place which contributed 
to the noises in the set was located in 
the B battery leads and connections, 
so I ended them by soldering the leads 
directly to the posts on the batteries. 
The set is not in a cabinet, being 
placed upon a table so that I have 
easy access to any unit should I de- 
cide to make experimental changes. 
Only the finest materials are used, 
and I considered the cost a secondary 
matter, because I knew that to get 
results, it was imperative that I pro- 
cure reliable and low loss apparatus. 
I always keep a log book, and jot 
down the settings of the secondary 
condenser dial for every station I 
hear. I attribute my success with the 
set to careful and long experiments, 
and contend that the only way to 
realize the utmost of any circuit is 
to learn every secret of its opera- 
tion. 

Mr. Kennedy on Sunday, Nov. 25, 1923, 
while amusing himself at the set around 
10:10 in the evening caught the London, 
England, broadcasting stations which op- 
erates under the call of 2LO. The only 



The Magazine of the Hour 

thing which impeded his continued recep- 
tion was the interference created by some 
nearby single circuit receiver which was 
being improperly operated. In the accom- 
panying photograph, we are publishing 
views of Mr. Kennedy's set and himself. 



Mr. F. Robert Zeit of 643 Garland 
Ave., Winnetka, 111., sends in a list of data 
and specifications on a super-regenerative 
circuit which he has devised, which should 
be of interest to any fan who possesses a 
collection of miscellaneous apparatus with 
which to experiment. He would be pleased 
to have letters from fans who construct 
this circuit. 

RADIO AGE, 

Gentlemen: 

The writer has been experimenting 
for some time with the various pub- 
lished hook-ups and simplifications of 
Armstrong's super-regenerative re- 
ceivers with a view of using this 
wonderful discovery in a moderate 
way in a set which the uninitiated 
could use successfully. 

All the published simplified cir- 
cuits have taken one element after 
another away until Mr. Muhleman of 
the Radio News left only one 1250 
turn inductance coil and two variom- 
eters as the result of long and labor- 
ious research. 

This encourages me in submitting 
this modest and easily operated super, 
which tunes well to all the current 
broadcasting wave lengths, from 200 
to 600 meters. 

My hook-up removes even the last 
large element of the original circuit, 
which Mr. Muhleman (Autoplex) re- 
tained, the 1250 turn coil, requiring 
neither a power tube nor a very high 
plate voltage. 

I enclose the circuit diagram of 
my single tube super-regenerative re- 
ceiver which has tremendous volume 
and excellent selectivity. It outdoes 
any three-tube set I have used in 
volume and clear reception, tuning 
to all wave lengths from 200 to 600 
meters with the greatest ease. 

Any fan with two variometers and 
a hard, high vacuum tube (I use U. 
V. 201), can rig up a trial circuit in 
a few minutes and hear the music or 
talk many times louder than if he sat 
in the broadcasting studio; in fact, 
the amplification is simply tremen- 
dous. 

Although I use a 0.006 M. F. fixed 
condenser across the tube any other 
value will do from 0.002 M. F. up. 

It is important that the rheostat 
be connected in the negative filament 
lead, as per diagram of circuit, or the 
super-effect is lost. 

No more than 45 volts should be 
used on the plate "B" battery unless 
the negative bias on the grid is in- 
creased by using a few cells of "C" 
battery in the grid return, but this is 
unnecessary because the volume with 
the 45-volt "B" battery is simply tre- 
mendous, providing sufficient filament 
current is used to heat the filament. 

No ground wire should be used. 

The aerial I used is an outside sin- 
gle wire 50 feet long. 



RADIO AGE for April, 1924 

An inside single wire 35 feet 
worked as well, even 10 to IS feet 
single wire inside aerial works effec- 
tively. 

Many different variometers were 
used and all worked but the loudest 
and clearest reception is obtained 
with variometers of large sized wire 
and about 60 turns on rotor and the 
same on stator. (High ratio of in- 
ductance.) 

Variometers with a minimum insu- 
lating material will probably do 
better. 

A standard Freshman variable grid 
leak with 0.00025 M. F. condenser 
was used and must be tried out for 
best results with the tube used. The 
pointer with my U. V. 201 between 
the fifth and sixth division line from 
the left worked best. 

Operation is extremely simple. The 
tube filament is heated to give a 
bright light, about one-half of the 
6-ohm resistance wire is used with a 
6-volt storage battery. 

The variometer dials (4-inch) are 
turned simultaneously and very slow- 
ly. After picking up a station the 
slightest move only is required to 
produce the super-effect. There is 
not much difference in the two dials 
settings when the super-effect is ob- 
tained and the same station can 
always be picked up again if these 
dial settings are logged. 

All howls and whistles abate com- 
pletely when a station is tuned in pro- 
perly by very slowly moving both 
dials. A little practice on local sta- 
tions is necessary before attempting 
to tune in distant stations. Local 
stations come in strong enough for a 
loud speaker. Distant stations come 
in with the volume of local stations 
on the regular regenerative set. 

Body effects vary a great deal and 
may be entirely absent, sometimes 
very marked. 

There are only two controls, the 
two variometers. Both hands are 
used. The super-effect is produced 
mainly by proper tuning with the grid 
variometer but the plate variometer 
is used at the same time, increasing 
the volume, finding thus with both 
dials the best position for the super- 
effect. It is very easy to pick up a 
station after which a very slight ma- 
nipulation of both dials will produce 
terrific amplification with the utmost 
clearness. Failure to produce this 
super-effect means that the filament 
is not heated sufficiently. 

The filament current, however, is 
not critical. After it has once been 
adjusted to give the super-effect it 
needs no further change for the whole 
range of wave length. 

Tuning is sharp, and nearby, pow- 
erful home stations may be heard 
faintly until the station wanted is 
tuned in and super-amplification 
reached. 

Not the slightest interference was 
noted by alternately tuning in a 345- 
meter station 40 miles away and a 
powerful 360-meter station 15 mile? 
away and another 360-meter station 
600 miles away 



Stations 1,000 miles away come in 
with fair volume. Five hundred- 
mile stations come in with the vol- 
ume of a home station with the aver- 
age regenerative set. 

Two variometers with large sized 
wire and about 60 turns on rotors and 
stators. 

6-ohm rheostat (without vernier.) 

U. V. 201 tube. 

Freshman variable grid leak and 
0.00025 grid condenser. 

Fixed mica condenser, 0.006. 

Storage "A" battery, 6 volts. 

"B" battery, 45 volts. 

50-inch single wire aerial. 

No ground wire. 



Now that we have some of the choicest 
kinks and experiences, we will pass on to 
some of the most unusual pickup records 
that we yet have had. The following 
letters will, from inspection, reveal that 
some of the most unusual permutations 
with radio sets were used, and also some 
of the longest average records of any ever 
yet printed in this department. 



RADIO AGE, 

Gentlemen: 

Noticing your "DIAL TWIST- 
ERS" column in the March issue, I 
thought I'd send in part of my log. 



The Magazine of the Hour 23 

I have a single tube set of my own 
construction, using a modified Zenith 
hookup, and with it I have accom- 
plished some unusual reception. Only 
the most distant stations are listed 
here: 

KHJ, KFI, KPO, KGW, KGO, 
KLX, KFAE, WKAQ, PWX, CFCN, 
CKCK, CKY, CFCA, CFCF, CJCM, 
KFAF, KFEL, KFFQ, and 156 others 
positively identified. The first five 
and WKAQ are heard regularly. 

A friend of mine has a similar set 
with an additional two-stage audio 
frequency amplifier, and among other 
DX stations he logged 2BD at Aber- 
deen, Scotland, on the last night of 
the tests. 

I am using a U. V. 201A for detec- 
tor and 22^4 volts on the plate. I 
find that it is the most sensitive and 
selective regenerative set I've ever 
tried, the stations coming in very 
loudly. At times WBZ and several 
others are heard with the phones off. 
KHT, KFI, KGO, KLX, KPO, KGW, 
CFCN, CKCK, CFCF, and WKAQ 
were all heard on the same night re- 
cently. I hear KFI and KHJ very 
consistently. 

Sincerely yours, 
CLARENCE R. WILLIAMS. 
433 Milton Ave., Janesville, Wis. 




AN EXPERT'S SUPER-HET 
Photo shows Arthur H. Lynch, raido expert, placing a variable grid leak in the 
second detector tube which helps clear up the quality of the reception of a super- 
heterodyne receiving set he has built according to his own plans. 



24 RADIO AGE for April, 1924 



,00(, 




Mr. Williams seems to cater to foreign 
stations if we are to judge from his list. 
It looks to us as though he is the holder of 
a most enviable one-tube DX record. 
Good work. 



From Wisconsin we jump \ n New Jer- 
sey with the following: 

RADIO AGE, 
Gentlemen: 

I was looking over your fine little 
magazine, the RADIO AGE, and saw 
some of the lists of stations heard. I 
would like to see my list scanned, and 
incidentally wish to say that- there 
may be a lot of skeptical fans when 
they see this list, but I can swear it 
is a bona fide one. I use a one-tube 
single circuit receiver. Enclosed here- 
with is the list of stations: 

WGAD, Essinada, P. R 

WKAQ, San Juan, P. R 

SPC, Rio de Janeiro, Brazil. 

2LO, London, England. 

PWX, Havana, Cuba. 

6KW, Tuninucu, Cuba. 

CFCN, Calgary, Alta., Can. 

CTCE, Calgary, Alta., Can. 

CHOC, Vancouver, B. C, 
and some station operating under (he 
call of PWB. My American recep- 
tions are: 

KFIU, KFZ, KGW, KFAD, KGO, 
KPO, KFI, KHT. KFIQ, KLS, 
KFDJ, KLP, KDYL, KFCY, KLZ, 
KFCK, KFKZ, KFIX, KFDL. 

In all I have received 247 stations, 
about 73 being over 100 miles away. 
Yours very truly, 
JOSEPH J. OSWALD. 
433 Emory Ave., Trenton, N. J. 



diately verify the log, as the stations oper- 
ating are in search of data of that nature. 
It also is a means of producing evidence 
of actual long distance reception to those 
who are incredulous. The list covers tre- 
mendous distances, and is certainly a 
remarkable one. We congratulate Mr. 
Oswald on his unusual feat. 



Mr. Oswald's letter contains reception 
that by many would be deemed impossible. 
We would suggest that hereafter if recep- 
tion of stations as distant as those of Mr. 
Oswald is accomplished, that fans imme- 



RADIO AGE : 

Gentlemen : 

After reading over my list of "sta- 
tions heard" I think that you, too, 
will feel that I should be admitted to 
your Royal Order of Dial Twisters. 

I have Q. S. L. cards from most of 
the stations listed and can vouch for 
the authenticity of my list. 

I use a single circuit regenerative 
set — detector and one step. Local 
stuff comes in on the speaker, and 
last week when I picked up KGO for 
the second time in a week, I pulled 
him in on the speaker loud enough to 
make out what he was saying at five 
feet from the loud speaker. Remem- 
ber — I use only two tubes! ! ! 

Guess that's all now, and hoping to 
be a Dial Twister next month, here's 
my best. 

73's OM, 

H. G. ENDE 
1801 Sedgwick St., Chicago, 111. 

Here's the list: WSY, KFAD, 
KYT, KFI, KPO, KHT, KGO, 
KFAF, DN4, 9ZAF, WDAL. WDAJ, 
WSB, WGM, KYW, WDAP, WGAS, 
WAAF, WTAZ, WBU, WMAQ. 
WWAY, WOAJ, WJAN, WTAS. 
WCBD, WTAY, WABA, WWAE 
WBAA, WOH, WGAZ, WOC, WOI 
WHAA, WBL, KFKB, WHAS, WGL 
WBZ, WCX, WWJ, WWI, KOP, 
WLB, WLAG, WCAL, WMAT, 
WHB, WDAF, KSD, WOS, WO\L, 
WNAR, WOQ. WOAW, KFKX, 
WOR. WTZ, WGY, WGR, WHAZ, 
2X1, WHN, WCAD, WHAM, WJY, 



The Magazine of the Hour 

WBT, WLW, WEAO, WSAI, 
WTAM, WJAX, WLAL, WKY, 
KDKA, WQAA, WCAE, WEAK, 
WDAR, WFAT, WDAA, WOAN, 
WMC, WBAP, WFAA, WOAI, 
WKAL, WPA, KZN, WHA, WAAK, 
WIAO, WPAH, PWX, CJCG, 
CFCA, CFCN, CKCK. 



Yea, verily, do we inscribe thy name 
on the Dial Twisters list, for it is no small 
thing in these days to receive Los Angeles 
in Chicago on a loud speaker, with two 
tubes. Keep up the good work. 



And, Mr. Printer, while ye are busily 
engaged in inscribing the name of Mr. 
Ende, stay thy hand and place also the 
name of the writer of the following letter, 
for he hath also done reception that com- 
mandeth great admiration: 
RADIO AGE. Inc. 
Dear Sirs: 

I am a subscriber to RADIO AGE 
and always read the section "Pickups 
by Readers." I am sending in a list 
of the stations that I heard on Mon- 
day, February 11. I have a single 
circuit two-tube A. F. A. set. The 
stations I heard and logged were: 
WOC, WLAG, WBAH, WOAW, 
WEAF, WGY, WCBD, WSB, 
WDAF, WOS, WHN, WOR, WKY, 
KFKX, 5XW, KFKB, WBAP, 
WBAV, WHAZ, WTAS, KFFQ, 
KLZ, WGR, KFI, KFGD. I think 
this is a good "coast to coast" record 
for a set of this kind. 

Yours truly, 
BENNIE SIVESIND. 
712 Maiden Lane, Decorah. Iowa. 



HAW! HAW! ha, ha, ha, eh 

Y' know, fellows, Mr. Rathbun just 
stepped into the office and told us a good 
one about that little "Baby Heterodyne" 
of his. He says he's been chuckling for a 
week about it. It goes something like 
this: 

Mr. Rathbun asked an editor of a well 
known daily newspaper as to how and what 
results he was getting with the Baby 
Heterodyne which had been built for him. 

The editor replied: "Nothing (an beat 
it. I did some of the most remarkable 
long distance last silent (Monday is silent 
in Chicago) night; you wouldn't believe 
it, but I got Louisville, Tenn., WHAS, on 
a loud speaker that night, and for one 
tube, it's sure some reception!" 

Now, Mr. Rathbun, the inventor of the 
"Heterodyne Baby," waited for us to 
laugh — but, to tell the truth, he couldn't 
see the joke at all. After a period of 
strained looks and highly charged air he 
said: 

"The joke is this: Monday night is 
certainly a fine night to do that kind of 
work. The only trouble is that it's silent 
night in Louisville on Monday, and believe 
me it sure is some reception when you get 
a station that's not operating at all. An' 
on the loud sneaker to boot!" 

Also, a fellow came in to this office and 
informed us that he wanted a back num- 
ber of the August issue. We told him we 
were all sold out, but that he could get 
the information from the RADIO AGE 



RADIO AGE for April, 1924 

ANNUAL, and he promptly bought the 
book, saying: 

"I had a copy of the August issue, from 
which I was building the Cockaday set, 
and when I turned my back the baby 
grabbed the most priceless radio periodical 
in the world and tore the thing into so 
many pieces that a whole Saturday after- 
noon and Sunday couldn't piece it to- 
gether." 



RADIO AGE, 
Gentlemen : 

I'm back again; this time with an 
SOS call. For goshsakes help me — ! 
Since my address appeared in the 
March issue, I've been swamped with 
letters. I can't answer them, they are 
countless. If they come in as fast as 
they did this week alone, I'll be in a 
padded cell. I enclose my hookup 
and a set of rules for building and 
operating the set, hoping that you will 
find room enough to publish both. 

I have now heard 185 stations with 
an aggregate mileage of over 158,000 
miles. I have heard 40 stations 1,000 
miles away; 11 of them over 2,000, 
the farthest being CYL of Mexico 
City, Mexico. 

Mr. Boyenga is all wrong! The 
single circuit coupler condenser is by 
far the best receiver. Look at Ken- 
neth Fischer's, Curtis Springer's and 
my record (ahem!). We single cir- 
cuit boosters gotta' hang together. 
Just to show you what a single circuit 
will do — my friend Jack Gray of this 
burg got 80 stations in two and one- 
half months with about 60 feet of 
wire coiled up and hung on a nail in 
his room. If you don't believe it, 
write him. His address is West Ohio 
Street, Bay City, Michigan. By the 
way — he's using my hookup too. 

Well, single circuiters, let's show 
'em that we don't have to take dust 
from the Reinartz or any other re- 
ceiver, including the "Super-het." 
Yours truly, 

RICHARD JONES. 
300 N. Warner Ave., Bay City, Mich. 

P. S. — Wise comeback, Pickups 
Editor, that was one on me! HI! 



Dick gives us a list of rules to follow 
out with the set shown in the accom- 
panying diagram. They are: 

1. A good grid leak is the key to 
success. Use a good grid leak and 
experiment until you find the one 
that gives the loudest signals. 

2. Solder all connections. 

3. Do not permit your set to whis- 
tle. If it is built right it should pick 
up clear music within 200 miles. If 
you let it whistle you'll spoil your 
neighbors concerts. Keep the coup- 
ling near the spilling point, but don't 
let it spill over. 

4. Be patient. If you can't pick 
up Hong Kong or Iceland the first 
night, don't be alarmed. Stick to it. 
(Think of the postage stamp — it 
goes a long way but sticks to the job 
until it gets there — The Ed.) 

5. Use standard well made parts; 
not cheap stuff. 

6. See RADIO AGE for January, 



1Q24, page 21, about causing squeals. 
You can get just as good results by 
not letting the set oscillate as by 
making it do so. (Last night KGO 
could be heard with the phones sev- 
eral inches from the ears, without 
tuning with the set oscillating.) 

7. If bothered by interference, 
build one of the wave traps in the 
January issue of RADIO AGE. 
Good Luck! 

RICHARD JONES. 



And now that we've gotten this non- 
sense out of our systems — let's read on: 

RADIO AGE, 

Pick-Ups and Hook-Ups Editor, 

Dear Sir: 

I read the pick-ups by readers in 
your magazine each month and enjoy 
reading them very much. 

I am- especially interested in the' 
single circuit receivers, as I own one 
from which I obtain very good re- 
sults. 

The following is a list of exactly 
forty stations received from 7 p. m. 
February 9 until about 1:30 a. m. 
February 10. 

I am omitting perhaps a half dozen 
or more of whose location or call 
letters I am not sure: 

WDAF, Kansas City, Mo. 

KDKA, Pittsburgh, Pa. 

WTAM, Cleveland, Ohio. 

WTAY, Oak Park, 111. 

KFJW, Towanda, Kansas. 

WOQ, Kansas City, Mo. 

WJAM, Cedar Rapids, Iowa 

PWX, Havana, Cuba. 

WLAG, Minneapolis, Minn. 

WSB, Atlanta, Ga. 

WHAS, Louisville, Ky. 

WSAI, Cincinnati, Ohio. 

WMAQ, Chicago, 111. 

WCAE, Pittsburgh. Pa. 



The Magazine of the Hour 

WFAA, Dallas, Texas. 

WMC, Memphis, Tenn. 

KYW, Chicago, 111. 

WEAF, New York, N, Y. 

WGY, Schenectady, N. Y. 

WTAS, Elgin, 111. 

KFMZ, Roswell, N. M. 

WOAI, San Antonio, Texas. 

KFKB, Milford, Kansas. 

WCAR, San Antonio, Texas. 

WFAH, Port Arthur, Texas. 

WDAP, Chicago, 111. 

KFMG, Coldwater, Miss. 

KGO, Oakland, Cal. 

KFLZ, Atlantic, Iowa. 

KFFG, Angeles Temple, Los An- 
geles, Cal. 

KFI, Los Angeles. Cal. 

WJAZ, Chicago, 111. 

KHJ, Los Angeles, Cal. 

WGR, Buffalo, N. Y. 

WHAA, Iowa City, Iowa. 

WBL, Anthony, Kansas. 

WPAL, Columbus, Ohio. 

WRC, Washington, D. C. 

KPO. San Francisco, Cal. 

WHAH, Joplin, Mo. 

Please note that no stations were 
received in my home state, Louisiana, 
in the adjoining state of Arkansas and 
only one from the state of Mississippi 
and none from Alabama, making il 
necessary to receive stations from 
greater distances. 

Sincerely, 

H. F. WILLIS. 
1200 Fairfieid Ave., Shreveport, La. 



25 



We print herewith a copy of a log of 
one of our readers which is probably one 
of the most systematic and carefully 
arranged records of stations heard, as yet 
submitted by our readers. We certainly 
admire the method of Mr. Kulp's listing 
of the stations, and feel sure that our 
readers would be interested in seeing how 
the other fellow does it. 




far 0V 20 O 

'forage bat 

Tubes,'** 



t v> •}. 



■fl'V Sf J 



"-ST* GrounA. 



Single Circuit HooKi/p 
Using One Tuba. ' 



The above cat is an exact reproduction of the circuit as submitted by Mr, Jones, 
with which he gets such good results. It is nothing more than a simple single circuit 
hookup such as many of our readers are using with great success. Mr. Jones particu- 
larly warns against operating the set with the tube oscillating, as he contends that 
better results and signals can be heard without the set acting as a transmitter. 



26 



RADIO AGE for April, 1924 



The Magazine of the Hour 



RADIO AGE, 
Pick-Ups Department, 
Gentlemen : 

I have read several numbers of 
your magazine and have been espe- 
cially interested in the records of the 
numbers of stations received in one 
night. Thinking that some of these 
records might be broken, I prepared 
to attempt this last night, Febru- 
ary 14, with the result as shown on 
the appended sheet. From 6 p. m. 
until 1 a. m. a total of forty-five sta- 
tions were heard, including ones from 
twenty different states and from two 
provinces in Canada, making up a 
total distance of twenty-five thou- 
sand three hundred and eighty (25,- 
380) miles. 

These were all heard on a three- 
tube set with no radio frequency 
amplification and practically all of 
them were audib'.e on a loud speaker. 
My set is home-made and uses the 
regular Armstrong regenerative cir- 
cuit. It is of the three-circuit type 
and consists of two variometers and 
variocoupler. 

I am enclosing log of all stations 
received last night and the time that 
thev were heard. This is no freak 



pick-up, as most of these can be 
heard any night on my set. 
Yours verv truly, 

JOHN H. KULP. 
223 Clifford Court, Madison, Wis. 



WOR . . 
WDAP 
WDAF 
KDKA 
WGR . 
WGY . 

WTAY 
KYW . 
WCX .. 
VVCAP 

WOAW 
WBZ .. 

woe .. 

KOP .. 
WHB .. 
WCAE 
WHAS 
WBAP 
WJAX 
WWJ . 
WSB .. 
WSAI . 
KSD .. 



.Newark, N. J. 
.Chicago, 111. . 
. Kans. City, Mo 
.E. Pittsb'gh, Pa 
.Buffalo, N. Y.. 
.Schenectady 

N. Y..., 
.Oak Park, 111 
.Chicago, III. 
.Detroit, Mich 
.Wash., D. C 
.Omaha, Neb. 
.Springf'd, Mass 
.Davenport, la. 
.Detroit, Mich.. 
.Kans. City, Mo 
.Pittsburgh, Pa. 
.Louisville. Ky. 
.Ft. Worth, Tex 
.Cleveland, 0. . 
.Detroit, Mich.. 
.Atlanta, Ga. . . 
.Cincinnati, 0. . 
.St. Louis, Mo. 



Distance 

805 
120 
370 
575 
490 

800 

120 
120 
350 
720 
370 
830 
125 
350 
. 370 
575 
370 
860 
420 
350 
715 
400 
310 



6:00 
6:03 
6:06 
6:08 
6:10 



20 
33 
38 
40 
56 
00 
02 
10 
15 
20 
30 
35 
43 
46 
55 
02 
07 
33 



WFAA 
WMC . 
WBT . 
WTAS 
KFIX . 

WEAF 
WCAL 
KFKX 
CFCA . 

WMAQ 
WHN . 
WJAZ 
WLW . 
KGO .. 
WFI ... 
WDAY 
WBAH 

CKY .. 

WKY . 
KHJ .. 
WIP .. 
KFI .. 



.Dallas, Tex 

.Memphis, Tenn. 
..Charlotte, N. C. 
..Elgin, 111 

.Independence, 
Mo 

.New York City. 
..Northfi'ld, Minn. 

.Hastings, Neb. . 

.Toronto, Ont., 
Can 

.Chicago, 111. . . . 

.New York City. 
..Chicago, 111. . . . 
, ^Cincinnati, O. . . 

.Oakland, Cal. . . 
, .Philadelphia, Pa. 

.Fargo, N. D. . . 
,.Min neapolis, 

Minn 

. .Winnipeg, Man., 

Can 

. .Okla. City, Okla. 
. .Los Angeles, Cal. 
. .Philadelphia, Pa. 
. .Los Angeles, Cal. 



825 
560 
700 
120 

360 
820 
230 
480 

510 
120 
820 
120 
370 
1,840 
800 
460 



40 
45 
57 
06 



9:10 
9:20 
9:24 
9:45 

9:50 
9:54 
10:00 
10:04 
10:15 
10:35 
10:50 
10:56 



130 11:15 



630 
720 

1,725 
800 

1,725 



11:40 
12:05 
12:20 
12:50 
12:58 




GENTLEMAN JIM'S MISTAKE 
When James J. Corbett recently spent an afternon w ; th Willie Hoppe, the 
champion billiardist, the veteran fighter inspected Willie's radio set. Willie patiently 
explained to Jim that the little bulbs when lighted brought in the old DX, which 
gave Corbett an inspiration. If a little tube does distance, what will a big one do? 
Our photo shows James J. Corbett with his idea of a real "DX'er" while Willie 
tried to show him his mistake. 



Total number 

of miles.. .25,380 ' 

RADIO AGE, 

Gentlemen: 

After reading in your February 
issue the wonderful DX-ing done by 
the Dial Twisters-, I find myself a bit 
discouraged. However, reviewing the 
circumstances I really can't say that 
my DX is so bad; hence this letter. 

It is interesting to note that I am 
using the same fundamental hook-up 
employed by E. L. Laudell. I stum- 
bled upon this circuit about nine 
months ago, and have been using it 
ever since with excellent results. 
During the summer months, I con- 
sistently logged Chicago, Atlanta and 
St. Louis in a location where other 
sets I had made refused to DX. Dur- 
ing the campaign against reradiation, 
I "junked - ' this set. and have re- 
vamped it in the following manner. 

I use as an untuned primary coil a 
coil of 10 turns, a secondary of 60 
turns shunted by a variable .0005 
condenser, and a tickler of 50 turns, 
which is shunted by a .00025 varia- 
ble condenser. All the coils are 
spider-web coils made by clamping 
the ends of 15 toothpicks between 
two circular discs as per the accom- 
panying illustration (Figure 5) wound 
with No. 26 SC. The primary and 
secondary are permanently coupled to 
each other, while the tickler is ad- 
justable. My record is as follows: 

Using this set in an experimental 
state, with a C301A tube with 21 volts 
on the plate, an aerial of 40 feet flat 
top, with a 35-foot lead-in, and located 
in a comparatively poor spot for DX 
reception, I contrived to log the fol- 
lowing stations with the locals all 
going full blast between 9:30 and 

II p. m.: WOO, WOS, WSB, WGY, 
WTAM, WDAP, KDKA, WLW, 
WKAR, PWX. The latter is my 
crowning achievement for both long 
distance and selectivity, as PWX 
operates on 400 meters and WOR 
operates on 405. 



RADIO AGE for April, 1924 



The Magazine of the- Hour 27 



I don't know whether the above 
is sufficient to land me among the 
Dial Twisters this month, but if it is 
not then I'll have to try again with a 
different set. 

Very truly yours, 

JOS. W. PFISTER. 
43 Menohan St., Brooklyn, N. Y. 



To tell the truth, Mr. Pfister, I don't 
quite feel that your list warrants your 
name being put on the DT list — but I do 
find that your letter contains a valuable 
hint as to the winding of coils, and also 
the little circuit (Figure 6) which will 
show the fans how their single circuit sets 
can be made more efficient by the addi- 
tion of this 10-turn coil which is used as 
a collector. This circuit is very much 
like that of the Simplifigon shown in the 
March issue in that respect, and does not 
radiate so violently. I am therefore put- 
ting your name on a list which I feel will 
carry more weight with readers, viz., the 
contributors' list, and hope that if you 
come across any other little kinks in the 
course of your experiments that you will 
let us hear from you. Come again. 



Now the Pick-Ups Editor has a soft 
spot for "kids" and when a young chappy 
sends in a scrawl telling of his record he 
just gloats, especially if it beats some 
fellow about 45 years old with a 10-tube 
super-heterodyne. It seems that the young 
bloods have the patience to sit into the 
wee hours of the a. m. — if their indulgent 
parents permit them to— and then the next 
day they sit down and painfully write up 
the list — they probably get more sport out 
of the list and letter than the preparation 
of their next day's homework in 'rith- 
metic, and send it into the Pick-Ups 
Editor. And if he possibly can, he pub- 
lishes them. Sometimes he has to, as in 
the case of Kenneth Fischer and Curtis 
Springer of Indianapolis, Ind. Anyhow — 
here's a list from another bug in his 
teens : 

RADIO AGE, 
Gentlemen: 

I get your RADIO AGE every 
month, and I looked over your lists 
and I think I can better some of them. 
I am fifteen years of age, and in a 
little over three weeks that we have 
had our set I have received 103 dif- 
ferent stations, some of which are 
nearly three thousand miles away, 
such as KPO, CFCI. 
In one night I received these 45 sta- 
tions: WCAD, WHAM, WTAY, 
WNAC, WIP, WDAR, WFI, WOO. 
WOR, WOC, WOS, WFAA, WHAS. 
PWX, KDKA, WCAE, WBZ, KYW, 
WHB, WGR, WHAZ, WEAF, 
WDAP, WGY, WJAR, WJAX, 
WSAI, WSB, WPAB, WJZ, WLW, 
WABB, WPS, WTAS, CHYC, WRC, 
WWJ, WCAB, KPO, WJAZ, WHN, 
WHK, WTAM, WDAF, WJAN. 
Sincerely yours, 

JOHN TOMLIN. 
303 Madison Ave., Atlantic City, N. J. 




ARMSTRONG'S SUPER-HETERODYNE 

Maj. E. H. Armstrong, designer of the famous regenerative radio circuit, is 

here shown with the six-tube super-heterodyne outfit which he demonstrated at the 

Engineers Society of New York. The outfit uses dry cells and a tiny loop enclosed 

in the cabinet. He has heard 2LO, London, with the receiver. See other photograph. 



From Atlantic City and its boardwalk 
we jump to the sunny clime of Texas in 
the following: 

RADIO AGE, 



Gentlemen: 

I have been reading the Hook-Ups 
and Pick-Ups in your magazine and 
thought I would send in my records. 
All stations have been picked up in 
the last week and a half. 

PWX, KFI, KDKA, KFFQ, 
KFKA,KFKX, KFKZ,KFKL.KGO, 
KHJ, KLZ, WAAW, WBAP, WLB, 
WCAL, WCAR, WCBD, WDAF, 
WDAP, WGY, WHAS, WHAZ, 
WHB, WJAM, WKY, WLW, 
WNAD, WOAI, WOAW, WOQ, 
WOS, WPAM, WSB, WTAM, 
WTAS, WTAY. 

I am using one WD 12 tube, and 
light socket for aerial. All stations 
heard more than twice and with 
enough volume to hear them plainly 
with one receiver. 

The set I am using is one of my 
own make. 



Yours truly, 

BIRELEY ROSS. 



RADIO AGE, 
Gentlemen: 

I have a crystal set of my own 
make, and here is a list of stations 
I picked up: KYW, WDAP, KFKX, 
WSAI, WLW, WCK, WTAZ, WJAM, 
WRAO, WSB, KSD, KDKA, WOAW 
and WMAV. 

I think that makes me a Dial 
Twister — don't you? 

Very truly, 
ROBERT SIGNAIGO 
4170 Connecticut St., St. Louis, Mo. 
P. S. — I can prove this any time 
you are in doubt. 

And that's that. Now before signing 
off, we want to again come into the 
Pick-Ups department. C'mon in; the 
waves are fine. 



28 



RADIO AGE for April, 1924 



The Magazine of the Hour 




n i i n ac 

rs 



3D 



SUBSCRIBERS, buyers of back numbers and buy- 
ers of our RADIO AGE ANNUAL, are hereby 
reminded that there are abroad in the land, a band of 
radio freebooters who pick up and carry off any good 
radio literature and illustrations they can find. They 
steal radio magazines from their neighbor's mail box 
in the apartment building vestibule. They pick them 
up from desks before the man to whom it was ad- 
dressed can get even a glance at it. We mention 
this for the very good reason that many of our readers 
have been forced to ask us to change the address to 
which their magazine was mailed in order that they 
might be sure of getting it from the postman in per- 
son. All readers who miss an issue of the magazine 
or fail to receive their annual in a reasonable time 
are requested to investigate conditions under which 
the mail is delivered and guard against theft by 
radio-klepto-maniacs. 

WE OWE apologies to Thomas J. Kennedy, 470 
West 159th Street, N. Y. In our February 
issue we published a photograph of Mr. Kennedy and 
his famous three-tube honeycomb regenerative re- 
ceiver. We also published a photographic back- 
panel view of the set. About three weeks after that 
issue of RADIO AGE was distributed over the 
United States and Canada we had a letter from Mr. 
Kennedy, saying that he was literally swamped with 
letters from RADIO AGE readers who wanted more 
information about his receiver. Mr. Kennedy said 
he could not possibly answer all these inquiries with- 
out a staff of stenographers. He sent us the wiring 
diagram of the circuit and you will find it in this 
issue of RADIO AGE. Just another of those inci- 
dents that prove we have a keenly alert and very 
extensive circle of readers. 

R<\DIO comes so near being a public utility at 
the present moment that it is doubtful whether 
great financial interests could monopolize manu- 
factures and broadcasting if they so desired and if 
they tried their level best to do so. With millions 
of Americans owning receiving sets for which they 
have paid a good round sum it is likely that it would 
be about as easy to take away their entertainment, 
or their free access to tubes, as it would be to deprive 
the babies of our American households of their milk 
bottles. When an art or an industry becomes so 
universal that conservative leaders estimate that 
about a quarter billion of dollars will be spent over 
the retail radio counters this year the business has 
outgrown private control. 



It is a national utility. It is an international neces- 
sity. It is the source of entertainment and education 
for all peoples. It guides the mariner on his danger- 
ous way in storm-swept sea lanes; it carries the mes- 
sage of the gospel on Sunday ; it flashes news around 
the world when cables and telegraph wires, fail ; it 
is the dancing master for rural swains and lassies; 
it tells the farmer when to get his ha} r in and when 
to sell his hogs at the top of the market. It signals 
the time to the punctual minded and it puts the chil- 
dren to sleep with bedtime stories. 

Now how can you monopolize a force like that? 

The American Telephone and Telegraph Company, 
one of the component parts ■ of the giant Radio 
Corporation, denies it is attempting to control broad- 
casting. The company insists, however, upon its 
ownership of various patent rights on devices essen- 
tial to broadcasting equipment. And the American 
Telephone and Telegraph Company demands certain 
fees from those of the broadcasters, whom it chooses 
to select as defendants to suits of injunction. 

Taking the A. T. & T. at its word, the company's 
statement that it does not seek a monopoly of broad- 
casting, is reassuring. The agitation caused by the 
company's two lawsuits against broadcasters in the 
East, became so general that it was discussed officially 
by Secretary Herbert Hoover, of the Department of 
Commerce. Mr. Hoover said, "I believe it safe to say, 
irrespective of claims under patent rights on appara- 
tus, that broadcasting will not cease and neither will 
our public policy allow it to become monopolized." 

We are betraying no secret when we repeat that 
any effort to divert or control sales of tubes that are 
essential to several different makes of standard receiv- 
ing sets is in restraint of the full development of what 
Mr. Hoover terms "an important incident of life." 
The Radio Corporation of America assures us that 
every effort is being made to keep ahead of the tre- 
mendous demand for UV-201 A tubes and that un- 
filled orders will be taken care of by April 1. That 
also will be reassuring to many thousands of fans 
who have been unable to go on with their operating 
and constructive work because they could not buy 
the necessary type of tube. 

It is possible that the radio public is too nervous — 
that it shrinks at shadows. That very public appre- 
hension, which has called forth these recent avowals 
from high places, is proof of the firm hold that radio 
has taken on our national life. As this magazine has 
said for two years: "Whoever is a friend of radio 
monopoly is no friend of radio." 




RADIO AGE for April, 1924 



The Magazine of the Hour 29 



White Radio Bill and Some Shadows 




(C) Henry Miller News Picture Service, Tnc. 

PLANNING RADIO REGULATIONS 
Congress has again undertaken the passage of a radio law that will take the place of the inadequate regulations in effect 
since 1912, when the radio art of today was scarcely dreamed of. Those in the picture, left to right, are the following 
members of the House of Representatives: Ladislas Lazaro, Louisiana; Schuyler Otis Bland, Virginia; Oscar J. Larson, 
Minnesota; George W. Lindsay, New York; Frederick R. Lehlbach, New Jersey; Wallace H. White, Maine, and Edwin 
L. Davis, Tennessee. 



THERE is one vigorous objection 
raised by broadcasters, newspapers 
and radio fans to the new radio 
bill introduced in Congress by Representa- 
tive Wallace White, of Maine. The point 
against which this opposition is aimed is 
the provision which would grant to the 
Secretary of Commerce full authority to 
regulate radio communication in the 
Unfted State and its possessions. 

With perfect faith in the fairness of 
Herbert Hoover, the present Secretary, it 
is still objected that nobody knows who 
his successors will be and that it is placing 
too much power in the hands of an 
individual. 

A recent radio referendum on the wet 
and dry controversy, conducted by E. F. 
McDonald, Jr., at the Zenith-Edgewater 
Beach Hotel, Chicago, brought almost 
50,000 paid telegrams into the station 
within about twenty-four hours. This 



3y FREDERICK SMITH 

remarkable incident is pointed to as an 
indication of the power of broadcast sta- 
tions to reach the people. 

[t is held out as proof that such 
tremendous power, multiplied by 561, 
representing the number of stations now 
licensed, should not be placed in the hands 
of any individual. It is contended that 
the regulation of the vast force brought 
into being with the advent of radio- 
telephony, should be given over for regu- 
lation by a commission, just as railroad 
affairs are governed by the Interstate 
Commerce Commission. 

Suing the "Independents" 

Interest in the control of broadcasting 
has been centralized recently by the 
apparent effort of the American Telephone 
& Telegraph Company to demonstrate to 
the public that it alone controls patent 
rights that justify that company in de- 



manding that all broadcasting stations 
shall, at the will of the A. T. & T., either 
pay the license fee demanded by A T. 
& T. or be liable to suit for injunction to 
restrain those stations from broadcasting. 

A. T. & T. has sued Station WHN, the 
jazzy entertainment center which holds 
forth in Broadway, N. Y. An injunction 
has been asked on the ground that WHN 
is using apparatus (as are all other broad- 
casters) on which A. T. & T. holds 
patent rights. 

In addition to attempting to stop "inde- 
pendent" broadcasters from using the air 
the American Telephone & Telegraph Com- 
pany proposes that broadcasters shall not 
use power or light wires for the transmis- 
sion of "wired wireless." The telephone 
and telegraph giant therefore sued the 
North American Company in the New 
Jersey courts, contending that that $40,- 
000,000 company had no right to serve 



30 



RADIO AGE for April, 1924 



The Magazine of the Hour 



No Monopoly in Broadcasting 
Says Secretary Hoover 

I AM in receipt of many requests for my views as to issues now before 
the courts bearing on the control of radio broadcasting. While it is 
impossible for me to express any opinion on particular issues that 
are before the courts or the Federal Trade Commission I can state emphat- 
ically that it would be most unfortunate for the people of this country to 
whom broadcasting has become an important incident of life if its control 
should come into the hands of any single corporation, individual, or combi- 
nation. It would be in principle the same as though the entire press of the 
country was so controlled. The effect would be identical whether this control 
arose under a patent monopoly or under any form of combination, and from 
the standpoint of the people's interest the question of whether or not the 
broadcasting is for profit is immaterial. In the licensing system put in force 
by this department the life of broadcasting licenses is limited to three months 
so that no vested right can be obtained either in a wave length or a license. 
I believe it is safe to say, irrespective t)f claims under patent rights on ap- 
paratus, that broadcasting will not cease and neither will our public policy 
allow it to become monopolized. 



"wired wireless" to those radio fans who 
preferred to get their radio joy by simply 
inserting a plug into the electric light 
socket and letting the big stations of the 
public utility corporation do the rest. In 
the latter suit A. T. & T. has a fight on 
its hands, if the fact that the North 
American Company has hired the best 
patent attorneys in the United States to 
contest the suit, may be taken as sig- 
nificant. 

In New York City it is proposed to 
build a municipal station in defiance of 
A. T. & T., which company, it is claimed 
has persistently put obstacles in the way 
of the establishment of such a station. 
The new station is to cost $50,000 and 
the municipal authorities promise a "fight 
to the finish." 

A Newspaper Opinion 
The danger in the situation is pointed 
out by the Chicago Daily News in an 
editorial published on March 13, in which 
it says: 

Though the world may not owe any 
man a living, it does provide him with 
free radio concerts here in the United 
States. The bedtime story, the mili- 
tary band and other messages from 
the loud speaker, like air and sun- 
shine, have escaped translation into 
the language of dollars and cents. 

Never! hless, certain kinds of radio 
entertainment are expensive. The 
waves in the ether set in motion by 
the golden voice of a famous operatic 
star may travel no farther than any 
other waves or exhibit superiority in 
any respect from a scientific point of 
view: still, they are costly, as a ru'e 
Consequently an organization among 
radio listeners in New York is gath- 
ering a music fund for the purpose 
of making accessible the most ex- 
pensive style of ether waves. In 
England it is necessary for a radio 
enthusiast to buy a license before 
acauiring his set. 

The radio public numbers now 
about ten millions. The ability of 
radio enthusiasts to pay for their 



concerts is a fact well considered by 
those interests which aspire to a mo- 
nopoly of the air. If efforts strictly 
to limit or squeeze out the independ- 
ent broadcasters should succeed these 
radio listeners doubtless would prove 
a richer concession than the famous 
Teapot Dome to any corporation ob- 
taining control of the ether whether 
by patent rights or by other means. 
The White radio bill, now before 
Congress, upon which hearings are 
being held, must be carefully scruti- 
nized and the public's rights against 
monopoly amply safeguarded if the 
measure is to pass. The people must 
demand protection against monopoly 
gained through bureaucratic favor 
and denial of the right of appeal. 
Here is a danger that apparently 
exists in the bill as it now stands. 

Mr. Hoover's Views 

As this issue of RADIO AGE goes to 
press the White bill is before the Mer- 
chant Marine and Fisheries Committee of 
the House. On March 1 1 Secretary 
Hoover made an address before this com- 
mittee which sets forth his own views of 
the proposed methods of regulating radio 
communication and his attitude toward 
monopolization of the industry and his 
opinions about centralized private control 
of broadcasting. Because of its import- 
ance to all radio interests we publish the 
statement: 

"It is urgent that we have an early and 
vigorous reorganization of the law in fed- 
eral regulation of radio. Not only are 
there questions of orderly conduct be- 
tween the multitude of radio activities in 
which more authority must be exerted in 
the interest of every user whether sender 
or receiver, but the question of monopoly 
in radio communication must be squarely 
met. 

"It is not conceivable that the Amer- 
ican people will allow this new born sys- 
tem of communication to fall exclusively 
into the power of any individual group or 
combination. Great as the development 
of radio distribution has been, we are 
probably only at the threshhold of the 



development of one of the most import- 
ant of human discoveries bearing on edu- 
cation, amusement, culture and business 
communication. It cannot be thought 
that any single person or group shall ever 
have the right to determine what com- 
munication may be made to the American 
people. I am not making this statement 
in criticism of the great agencies who 
have contributed and are contributing so 
much to the development of the art and 
who themselves have been well seized 
with the necessities of its development 
and proper use, but I am stating it as a 
general principle which must be dealt with 
as an assurance of public interest for all 
time. 

"Broadly, radio communication falls 
into two groups — that is, telegraphic com- 
munication by the use of the Morse code, 
and telephonic broadcasting. 

"Telegraphic communication may be 
conducted from individual to individual 
and is highly adapted for personal com- 
munication parallel with and competing 
with our other forms of electrical commu- 
nication. It may be found that some areas 
of communication can be best carried on 
by one single unit as experience has also 
shown to be the case in some other public 
utilities, but such cases should be con- 
ducted under Government control and 
supervision. Telephonic communication, 
however, is impossible between individuals 
from the Doint of view of public interest, 
as there are a very limited number of 
wave lengths which can be applied for this 
purpose and the greater usefulness of the 
available wave bands for broadcasting 
communication inhibits their use for per- 
sonal communication. We cannot allow 
any single person or group to place them- 
selves in position where they can censor 
the material which shall be broadcast to 
the public, nor do I believe that the Gov- 
ernment should ever be placed in the 
position of censoring this material. 

New Laws Needed 
"The problems involved in Government 
regulation of radio are the most complex 
and technical that have yet confronted 
Congress. We must preserve this gradu- 
ally expanding art in full and free devel- 
opment, but for this very purpose of 
protecting and enabling this development 
and its successful use, further legislation 
is absolutely necessary. 

"How profound the changes in this 
method of communication have been since 
the regulatory Act of Congress approved 
in August, 1912, is indicated by the fact 
that the whole telephonic application is 
practically a discovery since the act was 
passed. At that time radio was in consid- 
erable use as a telegraphic method of com- 
munication, more especially with ships, 
but there was not a single telephone broad- 
casting station in the United States. 

"Some indication of the development of 
the art is shown by the fact that at the 
time the act was passed 485 American 
vessels were equipped for transmission of 
telegraphic messages. There were 123 
land stations, of which one was trans- 
oceanic. There were 1.224 amateur sta- 
tions as I have said, all engaged in trans- 
mission of telegraphic signals. Today 
(Continued on page 38) 



RADIO AGE for April, 1924 



The Magazine of the Hour 



31 




WMat the Broadcasters 




are Doin£ 



«fe 




*+ J 



Inside the Studio 

Battling in the ring amid the cries of 
thousands and attempting to deliver a 
short address over the radio amid the 
quiet surroundings of a broadcasting 
studio, are altogether different, according 
to Mike McTigue, world's light heavy- 
weight champion boxer, who recently vis- 
ited WGY, the General Electric broad- 
casting station at Schenectady. 

Kolin Hager, chief announcer at the 
station, recalls it as one of the outstanding 
humorous events of the two years that the 
station has been in existence. 

"He was scheduled to deliver a few 
words on boxing," explained Mr. Hager. 
"Naturally, he was the last man in the 
world that we expected would suffer a case 
of 'michrophone fright,' but he did. He 
stepped up to the pick-up device, but he 
could not talk. 'I would rather face 
Dempsey than talk into that thing,' he 



said. "The result was that his trainer, 
who accompanied him to the studio, was 
compelled to read the written address." 

WGY is celebrating the second year of 
its existence. Mr. Hager has been in 
charge of the announcement since the 
institution of the station. 

"I made my first announcement on the 
night of February 21, 1922 — with many 
misgivings," said Mr. Hager. "I had re- 
hearsed just what I was going to say, 
twenty-five or thirty times, and then, when 
the time for the announcement arrived I 
said something altogether different from 
that which I had intended." 

The WGY studio is a comfortably fur- 
nished suite of rooms on the first floor of 
a new office building. The room from 
which come the songs and selections, the 
speeches and the readings, the comedies 
and the dramas, is furnished with noth- 
ing in the way of scenery such as is found 
in theaters, yet it was only a few days ago 



that the studio officials received a call 
from a traveling scenic artist who had 
been told that he might land a job at 
WGY painting scenery for the radio 

"One day the phone rang rather vigor- 
ously," said Mr. Hager. "I answered it 
and received this message: 'My husband 
is dead, thank God, and I wish you would 
broadcast the fact.' " 

Not so long ago the WGY players, a 
dramatic organization, built up for the 
broadcastirg of plays, delivered the com- 
edy, "Get Rich Quick Wallingford," in a 
most excellent manner. The story of the 
play has to do with the exploiting of an in- 
vention for "carpet covered carpet tacks" 
and it is really amusing, as all Wallingford 
stories are. Not long after the play was 
broadcast the studio received a visit from 
a woman who appea r ed very much excited. 

"You have exposed my secret," she 
said. "I have been working for a consid- 
erable length of time on this proposition 




Pho.o Topics N. Y. SCHOOLS ADOPT RADIO 

Children of Public School 76, Manhattan, who gave vocal selections over the radio under the direction of Miss May 
O'Conner from the Board cf Education Building. 



32 RADIO AGE for April, 1924 



The Magazine of the Hour 




SO THIS IS LONDON! 

This interesting photograph is the first to be taken at the studio of 2LO Broadcasting Station in London, showing the 
orchestra broadcasting. Note the disc-shaped microphone at the right. This station is frequently heard in the United States. 



and just as I get it perfected I hear you 
broadcasting it to the world, telling every- 
one about it." 

''Absolute silence in the studio is most 
essential," said Mr. Hager, "and it is with 
the utmost difficulty that we are able to 
impress this upon the artists or speakers 
who may be on the program. This silence 
must be maintained after the song or 
speech has been finished until the power 
has been cut off. But very often a vocal- 
ist will turn about, immediately after fin- 
ishing a song, and while standing in front 
of the microphone say, "Did I sing that 
all right?" 



New Canadian Station 
An epoch marking event in the history 
of radio in Canada — and one which very 
closely concerns local radio fans — is the 
opening of the largest and most powerful 
radio station in Canada, which went on 
the air in Ottawa on Wednesday evening, 
February 27th, with a complete and varied 
program of musical selections and a talk 
to listeners by Sir Henry W. Thornton, 
K.B.E., chairman and president of the 
board of directors. The new station ex- 
pects to have a range beyond that of any 
station in Canada, due not only to its up- 
to-date equipment, but also to the height 
of its aerial, which stands on the roof of 
the Jackson Building and reaches two 
hundred feet above the ground. 

The new station signs CKCH and broad- 
casts on a wave length of 435 meters. The 
initial program was relayed by station 
CHYC, Northern Electric, Montreal, on 
a wave length of 341 meters, so that radio 
listeners everywhere in Canada and the 
United States had no difficulty in receiving 
the program. 

Mr. W. H. Swift, Jr., radio engineer for 
the Canadian National Railways, is re- 
sponsible for the installation of the new 
sLalion, which will undoubtedly have the 
most varied and interesting programs in 
Canada. Broadcasting will take place 
Wednesday and Saturday evenings, with 
occasional church services on Sundays. It 
is the intention to make the Wednesday 



evening programs of a serious nature, in- 
cluding music of the highest type, ad- 
dresses, and possibly speeches in parlia- 
ment, while the Saturday evening program 
will be in a lighter vein. 

Station CKCH transmits news items as 
a part of its program, linking up with the 
radio receiving sets which have been in- 
stalled in the observation-library cars of 
Canadian National Railways transconti- 
nental trains. Arrangements have also 
been made whereby station CKCH will 
be at the disposal of the Canadian govern- 
ment at any time desired. 



"Abie's Irish Rose," given by the players 
themselves, who came up to the studio 
after the show was over at the Colonial 
Theater, Cleveland. 



Longest Radio Program 

It took only one concert, broadcast 
from the new studio of WJAX, Cleveland, 
Ohio, to prove to The Union Trust Com- 
pany, which owns and operates this sta- 
tion, that WJAX was getting out over 
the entire country from its new station 
just as successfully, and perhaps more so, 
than from its old location in the Citizens 
Building. 

The new studio is located upon the 
twentieth floor of the new 20-story Union 
Trust Building, the largest bank and office 
building in Cleveland, which is shortly to 
be occupied by The Union Trust Com- 
pany itself. 

The moving of the broadcasting station 
to the new building was simply the fore- 
runner of the moving of the entire bank. 

This first concert from the new studio, 
which was given upon the evening of 
Tuesday, February 26, was unique in 
many ways. In the first place, it proba- 
bly set a record for length of any single 
radio concert. It began at 7:30 in the 
evening of Tuesday, February 26, and 
continued without interruption until about 
two minutes before 5:00 on the morning 
of the 27th. 

This program was arranged entirely by 
the Cleveland News. About 125 perform- 
ers appeared upon this program. Besides 
soloists of every description, both vocal 
and instrumental, there were four different 
dance orchestras, a male chorus of 35 
voices, and an entire scene from a play. 



Henry Ford's Station 
Station KDEN, Dearborn, northern 
terminus of the Detroit, Toledo & Iron- 
ton Railroad radio system, now is operat- 
ing in a new home with an installation of 
advanced design setting new standards of 
efficiency for its rating. For the last three 
weeks, more than 400 messages per eight- 
hour day have been handled by this equip- 
ment with reliability and dispatch in con- 
junction with the company's radio offices 
at Springfield and Jackson, Ohio, 200 and 
300 miles distant on an air line, respec- 
tively. Capacity will be increased within 
a few months to 2,000 messages in eight 
hours by additional apparatus. An effi- 
cient printer telegraph system for relay- 
ing messages to the River Rouge offices 
automatically as they are typed by the 
receiving operator will be ready for use 
within a few weeks. Innovations further 
to increase completeness of the system 
may be expected from the continuous 
experimental work in progress. 

Commercial radio telegraphy for use by 
railroads is proving itself a practical and 
efficient means of business communica- 
tion between widely separated stations. 
More than that, it demonstrated during a 
recent heavy snowstorm an emergency 
utility for train dispatching which made 
possible operations of D., T. & I. trains 
on certain sections when land wires were 
down and service was disorganized on 
many railroads in the central states. 

Extensive use of radio for D., T. & I. 
commercial work has been in progress for 
about two years, the former equipment 
at Dearborn consisting of an antenna of 
70-foot mean height and transmitting ap- 
paratus of 150-watt power (increased last 
May from 50 watts). Now the antenna 
is 165 feet above the ground and the 
present use of 80 watts is far more effec- 
tive than the larger output of the old 
station. Equipment now being connected 



RADIO AGE for April, 1924 



The Magazine of the Hour 



33 



will increase the total output capacity to 
1,500 watts, this being divided between 
two separate sending equipments of 1,000 
and 500 watts capacity, respectively. 
D„ T. & I. stations, WNA at Springfield 
and WJQ at Jackson, Ohio, now have 500 
and 100-watt installations respectively. 
With the new equipment at Dearborn, 
direct communciation with Jackson is pos- 
sible, although the Jackson station was 
designed for operation only as far as 
Springfield, whence the messages for 
Detroit have formerly been relayed north 
At Dearborn three towers approximately 
450 feet apart and 165 feet above the 
base are placed in the form of a triangle 
Stretched along two sides of this triangle 
are the antenna wires, in sets of five 
wires each, and 360 feet in length. These 
furnish two transmitting or receiving 
aerials which may be used simultaneously 
If it is desired later to use triple equip- 
ment, the third side will be provided with 
wires. Antenna wires are of seven-strand 
No. 16 gauge phosphor bronze of superior 
strength and electrical efficiency. The an- 



fact that the Ford stations cannot be 
heard on a crystal or non-regenerative 
vacuum tube receiving set. The wave 
lengths used, 1,713 meters for Dearborn, 
1,875 for Springfield and 1,934 for Jack- 
son, are such that they interfere with no 
other commercial stations operating at the 
same time and are inaudible to receiving 
sets tuned in for radio broadcasting con- 
certs. 



In the South Seas 

The American radio broadcasting sta- 
tion will, in the near future, act as a 
powerful educational influence on the 
backward civilization of the islands of the 
Southern Pacific, predicts Maj. Gen. 
George S. Richardson, administrator of 
Western Samoa, under a mandate from 
the League of Nations to New Zealand. 
This statement was made in a letter from 
General Richardson to KGO, the Pacific 
Coast broadcasting station of the General 
Electric Company at Oakland, California, 
after he had listened to the entire program 
as the guest of Quincy F. Roberts, Amer- 



thousands of others who are isolated from 
the outside world by their residence in the 
tropical islards of the Paci'ic " 

WBZ Teaches Mu?ic 
So successful were the courses in Radio 
and Household Management broadcast 
last fall from Westinghouse Radio Sta- 
tion WBZ through the co-operation of the 
Massachusetts of University Extension, 
that a new course in Musical Appreciation 
was commenced Thursday, March 6. The 
course consists of eight weekly lectures 
given by Prof. Elisha S. Olmsted of 'Smith 
College. 

A feature of the course is the use of 
actual examples for the lectures. In other 
words, the radio students taking the course 
are not only told about the different forms 
of music with explanations of their char- 
acteristics but they actually hear music to 
illustrate such points. 

In order that a definite reaction can be 
had regarding the course, a fee of one 
dollar is charged to those wishing to par- 
ticipate. Each student receives printed 




CELEBRITIES AT A PARTY 
Thomas A. Edison who celebrated his seventy-seventh birthday, February 11, was tendered a complimentary luncheon 
at the Ritz-Carlton Hotel, N. Y., by moticn p'cture and other personalities. Photo shows, left to right — Will H. Hays, Thomas 
A. Edison, George Eastman, Senator Edward I. Edwards and Dr. Lee de Forest. 



tenna is held from sagging by 400-pound 
take-up weights. 

Under the water of the lake, encom- 
passed by the towers, more than a ton of 
copper wire is sunk paralleling the an- 
tenna wires above. This provides the 
ground counterpoise of the antenna sys- 
tem and is connected with the sending 
equipment. 

D., T. & I. commercial stations operate 
on the heterodyne principle — that is, the 
receiving tube must be oscillating at a 
frequency in cycles per second slightly 
different from the frequency of the waves 
received. The resultant combination of 
waves reduces the frequency from radio 
to audio. For instance, the incoming wave 
from Springfield station may be 175,300 
cycles per second, the Dearborn receiving 
set detector tube is adjusted to oscillate 
at 174,300 cycles per second and the dif- 
ference between the two, 1,000 cycles, 
results in a signal having a clear high- 
pitched whistle in the receiving telephones. 
The heterodyne principle accounts for the 



ican consul at Apia, British Samoa, on 
January 12. 

The entire program came in so clearly 
5,000 miles from the sending station that 
"Vailima," the old home of Robert Louis 
Stevenson, now the residence of Major 
General Richardson, has been named a 
"listening station" of KGO. The governor 
has become a radio fan and will equip 
his residence with a radio set. 

Consul Roberts, in a letter to KGO. 
stated that he invited General Richardson 
and his family to listen in the KGO and 
his excellency was astonished at the 
strength and clearness of the signals com- 
ing from a station 5,000 miles away. 

Major General Richardson's letter fol- 
low: 

"This evening I, with my wife and fam- 
ily, have been most pleasantly entertained 
by your company, and we feel very grate- 
ful to you and the excellent performers 
who so kindly gave their services to trans- 
mit their talent through the medium of 
your wireless installation to us, and to 



information which assists him in learning 
the subject and in being able to differ : 
entiate between the different types of 
music that he hears over the radio, on the 
stage, and in the concert hall. The money 
received is given to the instructor for his 
time and effort and to defray the expense 
of sending the printed matter to the stu- 
dent. 

In a course of this character that is 
broadcast, anyone having a receiving set 
can listen in but only those who send in 
the registration fee of one dollar will get 
the full benefit and receive credit at the 
end of the course. 



Rome to Washington 

Since February 20th, the Navy Com- 
munication Service at Washington has 
been in daily touch with the San Paolo 
radio station at Rome. This circuit, 
closed as unreliable some time ago, was 
recently reopened with "IDO," San Paolo, 
a new radio transmitting station in Italy. 



34 



RADIO AGE for April, 1924 



The Magazine of the Hour 



Radio Age Data Sheets 

By JOHN B. RATHBUN 



THERE has been a great demand for 
some form of radio reference work 
in which the more important fea- 
tures of radio engineering can be assem- 
bled in compact and easily accessible 
form, a sort of radio "pocket book." so to 
speak, which can be kept up to date by 
the addition of standard size pages cut 
from the successive issues of RADIO 
AGE. The old method of filing clippings 
cut from the regular reading pages was 
attended by many difficulties, for the clip- 
pings were irregular in size and difficult 
to file systematically. Again, there were 
often two different subjects on opposites 
of the page which made proper classifica- 
tion an impossibility, and worst of all, the 
matter would not fit a standard size binder. 
In this issue, RADIO AGE starts a 
new and valuable feature, a series of radio 
data sheets having standard size pages 
and which are printed only on one side 
so that they can easily be filed according 
to subject matter. They can be placed 
in standard binder covers, and when the 
series is completed the reader will have 
a very complete and up to date pocket 
book which thoroughly covers the various 
fields of radio. In order to conserve space 
and to be of value as a reference work, 
the text will be as concise and short as 
possible, a complete radio library within 
the limits of two covers. 

Indexing and Classification 

Owing to the many branches of radio 
subjects and the many subdivisions con- 
tained under each of these general sub- 
jects, a comprehensive indexing system 
was somewhat difficult to arrange. Much 
study was given to this problem before 
a suitable system was devised, and after 
going through the several library catalog- 
ing systems it was considered best to fall 
back on the old reliable lettering method 
in which each general subject is given a 
definite letter while the sub-subjects under 
this head are numbered. 

On the page opposite this introduction is 
an index of the general subjects covered, 
the indexing letters referring to the sub- 
jects being in the left hand column. The 
sub-numbers are not yet shown as they 
will be of little interest to the reader' ex- 
cept that they are of service in keeping the 
sheets filed in their proper order. 

As an example, we see from the index 
sheets that the subject of inductances and 
inductance calculation is under (F), hence 
when all the (F) sheets are assembled we 
will have a complete chapter or section on 
the subject of inductances. Under (G) 
will be found everything relating to aerials 
and aerial calculations, and so on. The 
number immediately following the letter 
refers to the location of the sub-subject 
or division under this number. 

Taking the subject of inductances as an 
example, and honeycomb coils in particu- 
lar, we will find that all data given in 
regard to honeycomb coils will be given 
under the number (20). Thus, the index 
for honeycomb coils will read: F-20, and 




SUIT CASE RECEIVER 

Demand for good portable sets is going to be heavy from now on. The photo- 
graph shows Miss Claire Patton with a six-tube receiver which is exceptionally 
compact. A loop aerial is contained in the small case. With head phones this 
outfit picks up stations 800 miles distant. The receiver was exhibited at the recent 
radio show in New York. 



all the F-20's must be collected together. 
Following the sub-number is the second 
number or page number by which the 
pages can be arranged to run in order 
under a given subject. Thus: F-20-8 
indicates that the sheet is on the subject 
of inductances, that (20) shows that 
honeycomb coils are referred to, and that 
the page number (8) is located in the 
eighth place under the section number 
(20). This is easily understood after a 
little experience and is the only practi- 
cable method of filing. 

Covers All Branches 
In order to cover as wide a range of 
subjects as possible within the first few 
issues, the sheets will not be published in 
alphabetical order, but will be somewhat 
scattered in regard to subject. We cannot 
very well begin with the letter (A) and 
lun through the list alphabetically, as this 
would prove tiresome and the sheets would 
have but little practical value until we 
got down to (G) or points beyond. We 
will attempt to give all branches as nearly 
equal representation as possible in the be- 
ginning so that the sheets will be of gen- 
eral interest. 

Owing to the necessity for expansion, 
and for the addition of supplementary 
sheets made necessary by future develop- 



ments, it will be necessary to allow for 
expansion gaps between the different sec- 
tions. The radio industry is developing 
too fast to permit of running the sheets 
solidly in the order of their page numbers. 
Thus, if you receive sheets F-20-1 and 
then F-20-5, do not think that you have 
missed the pages 2, 3 and 4. It is likely 
that these pages have been left open for 
new matter that might develop later on 
and which was therefore not originally 
contemplated. 

Beginners and Experts 
It is our intention to include both 
technical and popular matter in these 
sheets, both for the engineer and student 
and for the reader who only has a general 
experimental interest in radio. Notes on 
"trouble shooting" in tabular form and 
practical hints on construction will be 
among the helpful data sheets issued for 
the novice in radio. For the advanced 
student and engineer will be formulae, 
tables and graphical charts for computa- 
tions and laboratory test methods for de- 
termining the values of inductances, con- 
densers, etc. We aim to cover the field 
thoroughly and in detail. 

Starting with the letter (L) in the index 
and ending at (P) will be seen a very 
(Continued on page 36.) 



RADIO AGE for April, 1924 



The Magazine of the Hour 



35 



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RADIO AGE for April, 1924 



The Magazine of the Hour 



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(Continued from page 12.) 
iar with tuning and has learned how to 
handle a set, or for other reasons wishes 
to go a little deeper into the subject, a 
single circuit tuner, using an audion de- 
tector, is suggested. 

Ultra Audion Circuit 

Many single circuit sets will be found 
on the market, but the most simple of 
these is perhaps that which is known as 
the "Ultra Audion." This set, instead of 
using a crystal detector, makes use of the 
vacuum tube, and is known to be ex- 
tremely sensitive. Records show that dis- 
tances of two thousand or more miles have 
been covered with it and the reception 
was good and clear. This also is a very 
inexpensive set and is very easily tuned. 
It must, however, be remembered that 
the same rule in regard to the aerial con- 
struction applys to this set as that of the 
crystal. Much will depend upon the loca- 
tion and the aerial. This arrangement 
will cost less than many other single cir- 
cuit types, and if one wishes to assemble 
his own set, he will find it a very easy job. 
This circuit is shown in Figure 2, and for 
the benefit of those who wish to make 
their own set it is stated that instructions 
for its assembly have been published sev- 
eral times in previous numbers of this 
magazine. 

If, however, one wishes to purchase the 
set complete he will find that there are 
several types of ultra audion receivers on 
the market. Some of these make use of a 
tapped coil for the inductance and some 
use a variometer. The purchaser is ad- 
vised to select the latter for the reason 
that a much closer adjustment can be ob- 
tained with this form of inductance. He 
should also make sure that the variable 
condenser used has a vernier adjustment. 
This type of condenser and the variometer 
are not so important for local reception, 
but when tuning in long distance stations 
one will find them absolutely necessary. 

Other single circuit tuners may be used, 
of course, but from actual experience, th.; 
ultra audion has proven to be the easiest 
to construct and the most satisfactory and 
reliable of the single circuit tuners. It 



is of the regenerative type which assures 
one of more volume than can be obtained 
from a non-regenerative set. If volume 
enough for a loud speaker is desired, this 
can always be obtained by adding two 
stages of audio frequency amplification. 

Reinartz Is Popular 

The next set to be described should cost 
but little more than the ultra audio and 
has been proven out by thousands of radio 
fans. This is the Reinartz tuner as shown 
in circuits No. 3, 5 and 6. This also has a 
reputation for very long distance recep- 
tion and probably the beginner will find it 
a little more complicated than the ultra 
audion, but, in fact, it is no more so than 
many others. A careful study of the cir- 
cuit will soon convince one of this fact. 
Complete sets of this type are for sale in 
the radio stores and full instructions for 
making it have been published in former 
numbers of this magazine. 

The performance of this set is about on 
a par with the ultra audion, although there 
are many who claim it is better. The 
inductance is usually wound in the spider- 
web form to cut down the effects of dis- 
tributed capacity. Tuning is accomplished 
by means of two variable condensers and 
three switches as shown. This makes the 
tuning operation slightly more difficult be- 
cause of the added number of controls, 
but these, of course, make it possible to 
get a much closer adjustment, although 
it may take a little more time to do it. 

Regenerative Also Good 
The standard three-circuit regenerative 
set is the next in line. In this set the 
aerial, grid and plate circuits are all ad- 
justable and in this they are similar to 
the Reinartz. The standard three-circuit 
regenerative set is probably the oldest of 
all and there are many who consider it the 
best of the reasonably priced outfits. 

The principal parts used are first the 
variocoupler, the primary winding of 
which is adjustable, and is connected in 
the aerial and ground circuit. The energy 
is transferred from this aerial coil to the 
grid circuit by induction "»rd the induc- 



tance in the grid circuit is controlled by 
a variometer. Another variometer is 
placed in the plate circuit and is used to 
control regeneration. A study of circuit 
No. 4 will give a good idea of the ar- 
rangement of these parts. The standard 
three honeycomb coil circuit is also a 
three-circuit regenerative set and has the 
additional advantage of substituting coils, 
having a different number of turns for the 
purpose of adapting it to different wave 
bands. These coils are so arranged that 
they may be changed instantly and the set 
can be so adjusted that it will give recep- 
tion on wave lengths of any range. For 
the beginner who is interested in spark 
reception and can read the code, a set of 
this kind will be very interesting. 

Reflex Circuit 

Coming now to the higher priced re- 
ceivers for the man who cares not for 
expense, but wants to get good reception, 
there are many which can be recom- 
mended. Among these are the different 
reflex arrangements in which the tubes 
are made to do double duty, thus giving 
much more powerful reception with prac- 
tically half the number of tubes re- 
quired in other sets. One noticeable feature 
about these receivers is the fact that while 
vacuum tubes are used for the amplifica- 
tion, a crystal detector is used. 

This is because the crystal is known to 
be the best detector so far as clarity is 
concerned and because of the many steps 
of amplification used, the signal is greatly 
strengthened by the time it is ready to be 
rectified. As the crystal is very efficient 
on signals of great strength, it has been 
found to be the best for this class of 
service. Receiving sets of this type will 
bring in long distance broadcast programs 
on the loud speaker very nicely. 

If one builds his own reflex set, how- 
ever, he must use considerable care to get 
the proper apparatus and to see that the 
right condensers are used in the proper 
place, otherwise the balance of the dif- 
ferent parts of the circuit will be de- 
stroyed and the set will not function as 
it should. 



Data Sheets 

(Continued from page 34.) 
considerable amount of space that is de- 
voted to radio circuits or "hook-ups." 
This material will cover a great variety 
of receiver types and is arranged according 
to the class of circuit, whether regenera- 
tive, radio frequency, etc. Preceding each 
of these sections devoted to hook-ups will 
be explanatory matter on the principles of 
the circuits and data on their success- 
ful construction and operation. 



RADIO AGE and 
RADIO AGE ANNUAL 

A year's subscription to this magazine and a 
copy of the famous handbook of drawings and 
instructions on how to make standard receiving 
sets. 112 pages. 

All for $3.00 

Send today by check, registered mail or money 
order to 

RADIO AGE, Inc. 

500 N. Dearborn St. Chicago, 111. 



RADIO AGE for April, 1924 



The Magazine of the Hour 



39 



Two broadcasting stations are attempt- 
ing to solve the problem as to making 
broadcasting self-sustaining. They are 
WEAF, the American Telephone & Tele- 
graph station in New York, and WHB. 
the Sweeney School, Kansas City In 



V 



E S T A 

RadioBatteries 



You want a real battery; one that 
is guaranteed 100 to 120 amperes. 
6 volts. Get a VESTA. It will 
give complete satisfaction. 

6 Volts, 100 Amperes, $21.65 
6 Volts, 120 Amperes, 25.35 



Recharging Service 

In Chicago we have an estab- 
lished 24-hour service for bat- 
tery recharging. We call for and 
deliver all makes of batteries 



BRENNAN'S GARAGE 

and 
BATTERY STATION 

2135 Lincoln Avenue, 
Chicago, Illinois 

Phones: Lincoln 0351; Diversey 1858 




Each package contains enough ma- 
terial to engrave two complete sets of 
practically any circuit, including the 
Neutrodyne. 

Send fifty cents for sample package 
now. 

You will say it is worth many times 
the price. 

Save your set by marking each in- 
strument with an engraving that will 
become a permanent fixture on your set. 

Ask for it at your dealers and mark 
those battery terminals and save burn- 
ing out tubes. 

Can be placed on bakelite, rubber, 
wood, glass or any painted surface. 
Send fifty cents now to insure early 
delivery. 

ENGR AVO is the big liberal package. 
Just say ENGRAVO toyourdealerand 
he knows what you mean. 

Dealers and jobbers write for prices. 

CHERINGTON RADIO INDUSTRIES 

53 W. Jackson Blvd. Chicago, HI. 



New York a group of financially respon- 
sible gentlemen has undertaken the raising 
of a fund contributed by broadcast lis- 
teners with which to pay high class enter- 
tainers. A fund for the same purpose is 
sought by the Kansas City station through 
the medium of the sale of imaginary seats 
in an invisible theater. The school finances 
the station sufficiently to conduct it, undeT 
this plan, and the broadcast listeners are 
asked to pay for the entertainment. The 
price of "seats" is from $1 to $10. One 
of the inducements to buy "seats" is the 
proposal to send out advance programs to 
all those who pay more than the minimum 
of SI for (heir tickets. 



The Music War 



The National Association of Broad- 
casters gives out the following statement: 

"The controversy between the American 
Society of Composers, Authors and Pub- 
lishers and the National Association of 
Broadcasters, has broken out afresh and 
rapidly reached an acute stage. 

"The incident which renewed this fight 
was the forcing of a license to broadcast 
their music by the American Society upon 
the Edgewater Beach Hotel of Chicag > 
which they did not want and will not use 
Full details are given in the attached let- 
ter addressed to the American Society. 

"Aroused by these high handed meth- 
ods, John and Tracy Drake, proprietors 
of the Blackstone and Drake hotels of 
Chicago, called a meeting on February 
6th at the Blackstone Hotel, which was 
attended by the principal hotels, moving 
picture theater owners, dancing academies, 
music schools and broadcasting stations, 
in the Chicago district. 

"It was the first time in any part of the 
country that the interests have met jointly 
for the purpose of resisting the American 
Society. 

"The Chicago meeting adopted plans 
designed to more effectively combat the' 
increasingly unfair demands and tactics of 
the American Society. It is now felt that 
the measures adopted will check their 
avarice, and hold them strictly within the 
zone of fairly and justly administered 
enterprises. 

"The objectionable, coercive methods 
used by the American Society are not ap- 
proved by their more representative mem- 
bers. This is shown by the resignations 
of Waterson, Berlin & Snyder of New 
York, one of the six big publisher mem- 
bers, and Will Rossiter of New York, one 
of the oldest men in the music business, 
immediately upon their learning the facts 
Both letters of resignation are herewith 
attached. Henry Waterson sets forth his 
position in clear terms, and refuses to 
take part any longer. 

"Radio listeners are intensely interested 
in this weakening of the American So- 
ciety, indicating as it does the fast 
approaching time when five thousand 
American authors and composers and fif- 
teen hundred American publishers will 
have an equal chance with the two hun- 
dred and seventy-seven combined foreign 
and American authors and composers, and 
the forty-six combined foreign and Amer- 
ican publishers now constituting the 
American Society." 




SELECTIVITY 

Add a Ferbend Wave Trap 
to Your Set 

YOU can get "Distance." But can you 
keep it? Stop the interference. Don't 
let every Tom, Dick and Harry spoil 
the concert you are enjoying. Don't 
lose that DX Station so long "dialed for." 
Trap out the interfering Station with a 
Ferbend Wave Trap. Our guarantee 
plainly tells the story: 

We guarantee that the Ferbend 
Wave Trap, when properly con- 
nected to any workable receiv- 
ing set, will tune out any inter- 
fering station. 

Mr. John F. Parsons, 109 North Avenue 19. 
Los Angeles, California, writes: 

"I have installed the FERBEND WAVE 
TRAP I purchased from you some time ago and 
given it a thorough try-out. There are five 
broadcasting stations in this city, four of them 
[ can trap out by moving dial ten points, the 
other KFI, the most powerful one, I can silence 
by changing the dial twenty points. This station 
is heard on the Atlantic coast and Hawaiian 
Tslands." 

Make Every Night "Silent Night" 

The Ferbend Wave Trap is a valuable addi- 
tion to any set. It is designed and manufac- 
tured complete by us, after years of careful ex- 
perimenling. It is not to be confused with imi- 
tations hastily assembled from ordinary parts. 
The price is $8.50. Shipment made parcel post 
C. O. D. plus a few cents postage. If you pre- 
fer, send cash in full with order and we will ship 
postage prepaid. Send us your order today. 

Ferbend Electric Company 

16 East South Water Street, Chicago 

Descriptive Folder on Request 

FERBEND 



CLASSIFIE D ADV E RTIS EMENTS 

Six cerUs per wcrd per insertion, in advance. Name 

and address must be counted. Each initial counts 

as one wcrd. Copy must be received by the 15th of 
month fcr succeeding month's issue. 



RADIO ODDS AND ENDS 

No. 14 square tinned bus wire — 2 ft. lengths — 64 feet 
for $1.00. $1.20 set of 8 lettered binding posts — 60c. 
Spaghetti — 3 ft. lengths, red, yellow, green or black— 
7 lengths— 21 ft.— $1.00. 50 assorted brass screws, 
nuts, washers, lugs, etc. — 50c. All four items prepaid 
return mail — $3.00. Radio list for stamp — none free. 
Kladag Radio Laboratories, Kent, Ohio. 



BOOKS 

If you have not bought ycur Reinartz Book, fu'.Iy 
illustrated with hook-ups and clear description of 
hew to make this popular circuit, send $2.50 in money 
crder or currency and we will send you the booklet 
"Reinartz Radio'* and place you on the subscription 
list of Radio Age for one year. Address Radio Age, 
500 N. Dearborn Street, Chicago, III. 

15-20% DISCOUNT ON ALL STANDARD RECEIV- 
ERS, Fried- Eisemann Neutrodyne, $125.00: New Radi- 
Dlas, etc. Thomas Radio Co., Ill Dex St., Muncie, Ind. 



RADIO BATTERIES 

Super Radio A and B Circuit Batteries, which bring In 
long distance reception. Sold for cash or on payment 
plan. Write for prices and details. Radio Battery 
Corporation. 501-B Industrial Bank Bldg.. Flint. Mich. 




40 RADIO AGE for April, 1924 

WITH 



The Magazine of the Hour 



URERS 




CLE-RA-TONE SOCKET 

The Benjamin Electric Mfg. Company, 
Chicago, is producing a socket for vacuum 
tubes called the Cle-Ra-Tone. 

The tube-holding element of the socket 
floats on light springs which act as shock 
absorbers and neutralizes all interfering 
vibrations which ordinarily would cause 
"tube noises." The general effect is clearer 
reproduction. 

Vibrations which interfere with clear 
reproduction by the radio tube are of two 
kinds: (1) that caused by jar such as might 
occur from striking the receiving set with 
the hand or clicking the switch lever from 
one point to another; and (2) probably the 
more offensive kind called microphonic 
These microphonic vibrations might be' 
produced by footsteps in the same or ad- 
joining rooms or by street cars passing 
nearby or other such noises which are often 




in large cities, noticeable only by their 
absence as in the stillness of the night. 
Noises of this kind set the tube filaments 
in motion and are reproduced as very 
offensive disturbances over the 'phone. It 
is the ability of the new Benjamin Cle-Ra- 
Tone Socket to eliminate these microphonic 
noises which makes it of great value. 

This shock absorbing feature also pro- 
tects the lamp and is therefore excellent 
for portable receiving sets which are sub- 
jected to shocks in moving from place to 
place. The shock absorbing feature is in 
no way interfered with by stiff bus wiring 
because the wiring terminal base is sep- 
arated from the tube holding element by 
the tight springs mentioned above. The 
socket is made in two sizes — one for stand- 
ard base tubes and the other for UV199 
types. 



Variocoupler-Wave Trap 

The Electrical Research Laboratories, 
better known as the ERLA Company, 
have placed on the market a unit of the 
same standard of engineering as prevails 
in their reflex sets and accessories. 

This unit, known as the Selectoformer, 
is entirely in keeping with the general 
trend toward low loss, high grade turing 
units which are now being marketed. 



The unusual feature of the Selecto- 
former lies in the fact that it not only, 
serves the purpose of a variocoupler. but 
also can be used effectively as a wave trap, 
enabling the owner to minimize the inter- 
ference and cross talk caused by the many 
high power stations now in operation. 



^E7 AERIAL 




yet this absorbtion must not be so great 
as to absorb desired signals. Therefore, 
a different coupling co-efficient, as well as 
a different antenna coil constant, is neces- 
sary to get an efficient wave trap effect. 
Two separate and distinct requirements of 
a coupler and wave trap have been em- 



AN.T0P(0PEN) 

GR BOTTOM 

SWITCH FOR CUTTING 
INANDOUTOFTRAP 

(OPTIONAL) 



0005^l»tVAR.COND. (23 plates) 



~ GROUND 



S2 



EOT0R 



OA 



SET 



OG 



Due to the fact that this unit operate.- 
without taps, which every engineer knows 
causes losses in tuning circuits, its effi- 
ciency is very high both as an eliminator 
of interference and as a tuner. When 
used as a tuner, the connections are made 
much in the same manner as that of the 
fixed coupler of the Neutrodyne circuit, 
and when the operator desires to use the 
unit as a trap circuit for interference, the 
unit is shunted by a .0005 MF variable 
condenser, which should be of good design 
and low loss. The manufacturers claim 
that it increases the strength of the in- 
coming signals when it is so used. 

In the accompanying illustration the 
connections for using this unit as a pre- 
venter of interference are shown. W. J. 
Schnell, A. E., with the Erla Company, 
tells how this unit functions most effec- 
tively in the above circuit: 

"In perfecting the Selectoformer, the 
engineering staff found that the design 
required also provided the means for an 
efficient rejector, or wave trap. It is not 
difficult to put an absorbing device in the 
antenna system to stop certain ranges of 
frequencies, but if such an absorbing 
device is not carefully designed it will, 
like the old variocoupler, add its resistance 
to the input circuit. 

"As has already been demonstrated, this 
effect is found where very close inductive 
or conductive coupling is used. But in a 
wave trap closer coupling is necessary than 
would be used if the only object was the 
coupling of the two circuits for the trans- 
fer of energy, because it is desired to 
absorb energy from the antenna circuit, 



bodied in the Selectoformer by using two 
separate designs in one assembly." 



Two-Tube Sets for $18.50 

Simplicity of operation makes the new 
Crosley Model 51 Receiving Set very 
popular. It has detector and one-stage of 
audio frequency amplification, utilizing 
the Armstrong regenerative circuit. One 
multistat operates both tubes. It sells 
for $18.50 and is made by The Crosley 
Radio Corporation. 

Reports have already been received 
from owners of this new set, one man 
going so far as to testify that he has re- 




ceived 68 stations so far and many of 
them came in so loud he was able to use 
a loud speaker. This little set is built in 
a handsome mahogany cabinet and makes 
an ideal receiver for placing in the living 
room or any other part of the home. Its 
operation is so simple that children can 
use it with ease and any type of vacuum 
tube may be used with perfect results. 



RADIO AGE for April, 1924 
Farm Radio Figures 

REPLIES from 73 Illinois county 
' farm bureaus in a radio survey 
just completed by the Illinois Ag- 
ricultural Association, revealed that there 
are 20,845 radio receiving sets on farms 
in these counties. The survey would in- 
dicate that between 7 and 10 per cent of 
the rural population of the state have 
installed receiving sets. 

"The survey was made for the purpose 
of determining the extent of the use of 
radio on farms, the type of prog-ams most 
desired, practical benefits of the radio, 
and for the p'anning of programs to meet 
the demands of the constantly growing 
army of farm radio fans," state I. A. A 
officials. 

These farm radio sets tune in nightly 
on stations all over the United States. 



The Magazine of the Hour 



41 



Lakeside 
Radio Cabinets 



Many sets are unsightly in the homes without 
proper facilities for equipment. They un- 
doubtedly are good sets but why not make 
your set a real piece of parlor furniture. We 
specialize in radio cabinet work and if you 
have a problem in beautifying your set we 
can correct it for you. 




No. 500 Floor Cabinet Wood Mounting Panel 
can be removed if complete set is to be in- 
stalled or wood panel can be cut out to take 
Bakelite Panel up to 10x32 inches. 



List price. $70.00. 
Tone Finish. 



Mahogany or Walnut. Two 



Style B Table Cabinets Prices are on imitation 
Mahogany or Walnut. 

Cases 7" deep for 7" high panels. 

Length List Length List 

9 inches $3.20 24 inches $5.30 

12 inches 3.60 26 inches 5.70 

14 inches 4.00 28 inches 6.10 

15 iftches 4.40 30 inches 6.60 
21 inches 4.90 

Special Case 8 inches deep for panel 8 inches 
high, 40 inches long. Imitation Mahogany, 
$10.50. Genuine Mahogany, $17.50. 

Manufacturers, Jobbers and Dealers write 
for discounts. 



Lakeside Supply Co. 

DEPT. R 
73 West Van Buren St., Chicago, III 



Chicago, Davenport and St. Louis are 
mentioned most frequently, because they 
are near and easy for a small set to pick 
up, but many reports were given stating 
that farmers tune in on Kansas City, Dal- 
las, Ft. Worth, Jefferson City, Omaha, 
Pittsburgh, Philadelphia, New York and 
other broadcasting stations. 

The counties near broadcasting stations 
naturally show the most sets. Madison 
county, in the vicinity of St. Louis, has 
2,550 sets; Rock Island county, near 
Davenport, has 900, and in Henry county, 
also near Davenport, the report shows that 
nearly one-third of the entire farm popu- 
lation has sets. 

Only about 25 per cent of the farmers 
owning radio sets make their own, the rest 
being manufactured sets, the survey 
shows. 

One of the questions asked in the survey 
was, "What sort of radio programs do such 
gatherings use the most and like the best?" 
The almost invariable reply to this was, 
"Musical programs and occasionally good 
lectures." 

Replies from most of the counties indi- 
cate that many farmers tune in on the 
weekly farm lectures broadcasted each 
Tuesday night from station KYW, Chi- 
cago, under the auspices of the American 
Farm Bureau Federation. 

Individual farmers, farm bureaus and 
banks tell of practical benefits from the 
daily market and weather reports. Mont- 
gomery county, near St. Louis, furnishes 
this example: 

"The First National Bank of Raymond, 
Illinois, has a radio set and gets the open- 
ing livestock market at 9:30 a. m. The 
manager of the co-operative shipping as- 
sociation keeps in close touch with the 
market report at East St. Louis, and sev- 
eral times has received the market report 
at 9:30, called in one or two cars of hogs 
and hit a good market at East St. Louis 
the next day. On several occasions this 



made the farmers from $50 to $100 per 
car more money for their hogs." 

The returns from Madison county 
state: "The reports keep the farmers in 
closer touch with the markets and they 
are not the prey of buyers who may come 
along and offer below the market for hogs 
or cattle." 

One point that was stressed was the 
necessity of having farm programs early 
in the evening, since the 10 o'clock pro- 
grams are rather late for farmers. 



5-in-l Unit 

s 722 




This wonderfully efficient Audio- 
Amplifying Unit consists of — 
Transformer — Rheostat and Socket 
all ready for panel mounting. Will 
save you time, trouble, expense and 
space in building your set. Gives 
most efficient results. Every 3-in-l 
Unit fully tested and guaranteed. 
One Unit will amplify your crystal set 'for 
loud speaker use. Specially wired Unit for 
Reflex work. Mail orders promptly filled. 

DEALERS - JOBBERS: We have a real 
proposition for you on SUPERADIO sets and 
parts. 



Distributors 
36 S- State St. Chicago, 111. 




w^ 



Howard Parts 

No. 1001— Rheostat $1.10 

No. 1003 — Potentiometer 1.50 

No. 1002— Micrometer 1.50 



Ask Your Dealer for Howard Parts. 
He Will Be Glad to Show Them. 
JOBBERS WRITE FOR DISCOUNT 



No. 1004 

Multi Terminal Receiver Plug, 
instantaneous connection for as 
many as six pairs of standard 
receiver tips $2.00 

Patd. Aug. 28, 1923 




HOWARD RADIO COMPANY, Inc. 



4248 North Western Avenue, Dept. A 

Always Mention RADIO AGE When Writing to Advertisers 



CHICAGO, ILL 



42 



RADIO AGE /or April, 1924 



The Magazine of the Hour 




^JLT" 



B. C. L. Everywhere, USA. 

Question: I desire to write your de- 
partment for information, and would like 
to know the best way to go about it. 
Kindly inform me if there is a charge for 
this information. How many questions 
shall I ask in one letter? Is a stamped 
addressed envelope necessary with my 
inquiry? Please give me some informa- 
tion on the proper way to request the 
services of your technical department. 

Answer: The Technical Office will be 
glad to answer inquiries of subscribers 
free of charge ; if you are a non-subscriber 
we must request that you enclose fifty 
cents for each such inquiry as you send 
in, together with a stamped addressed 
envelope. We find that it is necessary 
to do this in order to assure proper atten- 
tion to our regular subscribers. When 
writing, don't put down everything that 
comes into your head — stick to the par- 
ticular subject you are asking about. If 
your question is about a set, enclose a 
diagram of the receiver to get the most 
accurate answer. Don't ask questions 
about commercial manufactured sets — 
write the manufacturer for that informa- 
tion. Before writing, always look back 
into your past issues of RADIO AGE (if 
you don't have them, you can get the 
ANNUAL to look them up) to see if your 
question has not been answered before. 
Write your questions on a separate sheet 
if they are to be sent to this magazine 
with a subscription or an order. Isometric 
sketches outside of those appearing in the 
RADIO AGE and the ANNUAL are not 
available. We will print popular circuits 
in isometric form from time to time. 
Write your inquiries on one side of the 
paper only; don't forget to enclose a 
stamped addressed envelope, and make 
them as brief as possible. We'll both 
save time that way, and you'll get your 
answer sooner. Address all your inquiries 
to RADIO AGE, Inc. Technical Office, 
Room 730—510 N. Dearborn St., Chi- 
cago, 111. 

Now, let's go! 



C. S. Chicago, 111. 

Question: I made the Rosenbloom 
Circuit which was printed in the January 
issue of the RADIO AGE. I have re- 
ceived good results with respect to vol- 



ume, but have not received distant